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Mitsubishi
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LGH 15-200RX4
Service Manual [eng]
77 pgs11.05 Mb0
TECHNICAL MANUAL
220 pgs5.88 Mb0
Table of contents
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Mitsubishi LGH-15...200RX4, RX4 TECHNICAL MANUAL

 

Lossnay Unit

i

CONTENTS

CHAPTER 1 Ventilation for Healthy Living
1. Necessity of Ventilation ...................................................................................................................................... 2
4. Ventilation Performance ...................................................................................................................................... 8
5. Outdoor Air (ventilation) Load .............................................................................................................................. 10
CHAPTER 2 Lossnay Construction and Principle
1. Construction and Features of Lossnay .............................................................................................................. 16
2. Construction and Principle of Core ...................................................................................................................... 16
3. Calculation of the Total Heat Recovery Efficiency .............................................................................................. 18
4. What is a Psychrometric Chart? ........................................................................................................................ 19
5. Calculation of Lossnay Heat Recovery .............................................................................................................. 20
CHAPTER 3 General Technical Considerations
1. Lossnay Heat Recovery Effect ............................................................................................................................ 22
2. Example Heat Recovery Calculation .................................................................................................................. 24
3. Calculation of Lossnay Economical Effects ........................................................................................................ 26
4. Psychrometric Chart .......................................................................................................................................... 28
5. The Result of No Virus (phage) Cross Contamination for the Lossnay Core and Determining
Resistance of the Lossnay Core to Molds .......................................................................................................... 29
6. Flame-proofing Properties of Lossnay Core ...................................................................................................... 31
7. Lossnay Core’s Soundproofing Properties Test .................................................................................................. 33
8. Change in Lossnay Core Over Time .................................................................................................................. 34
9. Comparison of Heat Recovery Techniques ........................................................................................................ 36
CHAPTER 4 Characteristics
1. How to Read the LGH Series Lossnay Characteristic Curves ............................................................................ 40
2. Calculating the Static Pressure Loss .................................................................................................................. 40
3. How to Obtain Efficiency from Characteristic Curves ........................................................................................ 44
4. Sound .................................................................................................................................................................. 45
5. NC Curves (LGH-RX
4 Series) ............................................................................................................................ 51
CHAPTER 5 System Design Recommendations
1. Lossnay Usage Conditions ................................................................................................................................ 58
2. Noise Value of Lossnay with Built-in Fans .......................................................................................................... 59
3. Attachment of Air Filter ...................................................................................................................................... 59
6. Transmission Rate of Various Gases and Related Maximum Workplace Concentration .................................. 60
7. Solubility of Odors and Toxic Gases, etc., in Water and Effect on Lossnay Core .............................................. 61
8. Positioning of the Supply/Exhaust Fans and the Air Transmission Rate
(excluding moisture resistant total heat recovery units) ...................................................................................... 62
9. Combined Operation with other Air Conditioners ................................................................................................ 63
10. Automatic Ventilation Switching .......................................................................................................................... 64
11.Vertical Installation of LGH Series ...................................................................................................................... 65
12. Installation of Supplementary Fan Devices After Lossnay Unit .......................................................................... 66
ii
CHAPTER 6 Examples of Lossnay Applications
2. Medium Size Office Building .............................................................................................................................. 71
3. Multipurpose Tenant Building .............................................................................................................................. 74
4. Urban Small-Scale Building ................................................................................................................................ 77
5. Hospitals ............................................................................................................................................................ 78
6. Schools .............................................................................................................................................................. 80
7. Hotels (convention halls, wedding halls) ............................................................................................................ 82
8. Public Halls (combination facilities such as day-care centres) .......................................................................... 85
CHAPTER 7 Installation Considerations
1. LGH-Series Lossnay Ceiling Embedded-Type (LGH-RX
4 Series) ...................................................................... 86
2. Building Lossnay Unit Horizontal-type (LU-500) ................................................................................................ 89
CHAPTER 8 Filtering for Freshness
2. Data Regarding Dust .......................................................................................................................................... 92
3. Calculation Table for Dust Collection Efficiency of Each Lossnay Filter ............................................................ 93
4. Comparison of Dust Collection Efficiency Measurement Methods .................................................................... 95
5. Calculation of Dust Concentration ...................................................................................................................... 97
CHAPTER 9 Service Life and Maintenance
2. Cleaning the Lossnay Core and Pre-filter .......................................................................................................... 100
CHAPTER 10 Ventilation Standards in Each Country
1. Ventilation Standards in Each Country ................................................................................................................ 102
2. U.S. ...................................................................................................................................................................... 103
3. U.K....................................................................................................................................................................... 103
CHAPTER 11 Lossnay Q and A .......................................................................................................................... 106

CHAPTER 1
Ventilation for Healthy Living

2
CHAPTER 1 ● Ventilation for Healthy Living
Fresh outdoor air must be introduced constantly at a set ratio in an air conditioning system. This fresh air is introduced to be mixed with the return air from the room, to adjust the temperature and humidity, supply oxygen, reduce body and other odors, remove tobacco smoke and to increase the cleanness of the air. The standard ventilation (outdoor air intake) volume is determined according to the type of application, estimated number of persons in the room, room area, and relevant regulations. Systems which accurately facilitate these requirements are increasingly being required to be installed in buildings.

1. Necessity of Ventilation

The purpose of ventilation is basically divided into “oxygen supply”, “cleaning of air”, “temperature control” and “humidity control”. Cleaning of the air includes the elimination of “odors”, “gases”, “dust” and “bacteria”. The needs of ventilation are divided into “personal comfort”, “assurance of environment for animals and plants”, and “assurance of environments for machinery and constructed materials”. In Japan legal regulations regarding ventilation are set in the Building Srandard Law Enforcement Ordinance and the “Building Management Law” for securing a sanitary environment in buildings. These are in general agreeance with similar regulations in other countries.
1.1 Room air environment in buildings
In Japan, the Building Management Law, a law concerning the sanitary environment of buildings, designates eleven applications including offices, shops, and schools with a total floor area of 3,000 m
2
or more, as buildings. According to this law maintenance and management of the ventilation and water supply and discharge according to the Environmental Sanitation Management Standards is obligatory.
The following table gives a specific account of buildings in Tokyo. (Tokyo Food and Environment Guidance Center Report)
Specific Account of Buildings in Tokyo (March, 2003)
Note: Excludes buildings with an expanded floor space of 3,000 to 5,000 m
2
in particular areas.
The ratio of results of the air quality measurement public inspection and the standard values that were not met (percentage of unsuitability) for the approximately 500 buildings examined in 1980 is shown in the chart at the right.
There was a large decrease in unsuitable percentages of floating particles, but there was almost no change in temperature and carbon dioxide. Values for temperature, ventilation, and carbon monoxide almost entirely cleared the standard values, and are excluded. The study from 2002 shows the item with the highest percentage of unsuitability as temperature with 2.7%, followed by carbon dioxide at 22.8%.
70
60
50
40
30
20
10
0
Percentage of unsuitability (%)
76 77 78 79 80 8171 72 73 74 75
82
83 84
85
86
87
88 899091 92 93 94 95 96 97 98 99 00 01 02
(year)
relative humidity
carbon dioxide
temperature
carbon monoxide
ventilation
floating particles (tobacco smoke)
Percentage of unsiutability of air quality by year
(From reference data in the 2003 edition of the “Water Supply
Division, Dept. of Localized PublicHealth, Tokyo Metropolitan Government, Bureau of Public Health”)
Number of buildings %
Offices 1,467 56.7
Shops 309 22.0
Department Stores 63 2.4
Schools 418 16.2
Inns 123 4.8
Theaters 86 3.3
Libraries 12 0.5
Museums 11 0.4
Assembly Halls 63 2.4
Art Museums 8 0.3
Amusement Centers 27 1.0
Total 2,587 100.0
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CHAPTER 1 ● Ventilation for Healthy Living
Effect of carbon monoxide (CO) 10,000 ppm = 1%
Concentration (ppm)
Effect of concentration changes
0.01 - 0.2 Standard atmosphere.
5 Considered to be the long-term tolerable value.
10
The Building Standard Law of Japan, Law for Maintenance of Sanitation in Buildings. Environmental standard 24-hour average.
20
Considered to be the short-term tolerable value. Environmental standard 8-hour average.
50
Tolerable concentration for labor environment. (Japan Industrial Sanitation Association)
100
No effect for 3 hours. Effect noticed after 6 hours. Headache, illness after 9 hours; harmful for long-term but not fatal.
200 Light headache in the forehead in 2 to 3 hours.
400 Headache in the forehead, nausea in 1 to 2 hours; headache in the back of head in 2.5 to 3 hours.
800 Headache, dizziness, nausea, convulsions in 45 minutes. Comatose in 2 hours.
1,600 Headache, dizziness in 20 minutes. Death in 2 hours.
3,200 Headache, dizziness in 5 to 10 minutes. Death in 30 minutes.
6,400 Death in 10 to 15 minutes.
12,800 Death in 1 to 3 minutes.
Several 10,000 ppm
This level may be found in automobile exhaust.
(Several %)
Apprpx. 5 ppm is an annual average value in city areas. This value may exceed 100 ppm near roads, in tunnels and parking areas.
Concentration (%) Standards and effect of concentration changes
Approx. 21 Standard atmosphere.
20.5
Ventilation air volume standard will be a guideline where concentration does not decrease more than 0.5% from normal value. (The Building Standard Law of Japan)
20 - 19
An oxygen deficiency of this amount does not directly endanger life in a normal air pressure, but if there is a combustion device in the area, the generation of CO will increase rapidly due to incomplete combustion.
18 Industrial Safety and Health Act. (Hypoxia prevention regulations.)
16 Normal concentration in exhaled air.
16 - 12 Increase in pulse and breathing resulting in dizziness and headaches.
15 Flame in combustion devices will extinguish.
12 Threat to life in short term.
7 Fatal
In the case of Japan, an Instruction Guideline based on these regulations has been issued, and unified guidance is carried out. Part of the Instruction Guideline regarding ventilation is shown below.
●
The fresh outdoor air intake must be 10 m or higher from ground level, and be distanced appropriately from the exhaust air outlet. (Neighbouring buildings must also be considered.)
●
The fresh outdoor air intake volume must be 25 to 30 m3/h·person in design.
●
An air volume measurement hole must be installed at an effective position to measure the treated air volume of the ventilating device.
●
The position and shape of the supply diffuser and return grille must be selected so the air environment in the room is distributed evenly.
1.2 Effect of air contamination on human bodies
Effect of oxygen (O2
) concentration
4
CHAPTER 1 ● Ventilation for Healthy Living
Effect of carbon dioxide (CO2)
Note: According to Facility Check List published by Kagekuni-sha.
1.3 Effect of air contamination in buildings
●
Dirtiness of interior New ceilings, walls and ornaments will turn yellow in one to two years. This is caused by dust and the tar in tobacco smoke.

2. Ventilation Standards

The legal standards for ventilation differ according to each country. Please follow the standards set by the country. In the US, Ashrae revised their standards in 1989 becoming more strict. In Japan, regulations are set in the The Building Standard Law of Japan Enforcement Ordinance, the so-called “Building Management Law” for securing a sanitary environment in buildings. According to the Building Standards Law, a minimum of
20 m
3
/h per person of ventilation air is required.
Concentration (%) Effect of concentration changes
0.03 (0.04) Standard atmosphere.
0.04 - 0.06 City air.
0.07 Tolerable concentration when many people stay for long time.
0.10
General tolerable concentration. The Building Standard Law of Japan, Law for Maintenance of Sanitation in Buildings.
0.15 Tolerable concentration used for ventilation calculations.
0.2 - 0.5 Observed as relatively poor.
0.5 or more Observed as the poorest.
0.5 Long-term safety limits (U.S. Labor Sanitation) ACGIH, regulation of laborer offices.
2 Depth of breathing and inhalation volume increases 30%.
3Work and physical functions deteriorate, breathing doubles.
4 Normal exhalation concentration.
4 - 5
The respiratory center is stimulated; depth and times of breathing increases. Dangerous if breathed in for a long period. If an O
2 deficiency also occurs, trouble will occur sooner and be more dangerous.
8
When breathed in for 10 minutes, breathing difficulties, redness in the face and headaches will occur. The trouble will worsen when there is also a deficiency of O
2.
18 or more Fatal
There is no toxic level in CO2 alone. However, these tolerable concentrations are a guideline of the contamination estimated when the physical and chemical properties of the air deteriorate in proportion to the increase of CO
2.
5
CHAPTER 1 ● Ventilation for Healthy Living

3. Ventilation Method

3.1 Ventilation class and selection points
An appropriate ventilation method must be selected according to the purpose. Ventilation is composed of “Supply air” and “Exhaust air” functions. These functions are classified according to natural flow or mechanical ventilation using a fan (forced ventilation).
Classification of mechanical ventilation
Classification of ventilation (according to Building Standards Law)
1. Class 1 ventilation
Fresh outdoor air is mechanically brought in and simultaneously the stale air in the room is mechanically discharged.
2. Class 2 ventilation
Fresh outdoor air is mechanically brought in and the exhaust air is discharged from the exhaust air outlet (natural).
3. Class 3 ventilation
The stale air in the room is mechanically discharged and simultaneously fresh outdoor air is mechanically introduced from the supply air diffuser (natural).
Ex. of application
•Ventilation of air conditioned rooms. (buildings, hospitals, etc.)
•Ventilation of room not facing an outer wall. (basement, etc.)
•Ventilation of large room. (office, large conference room, hall, etc.)
• Surgery theatre.
• Clean rooms.
• Foodstuff processing factories.
• Local ventilation in kitchens.
•Ventilation of hot exhaust air from machine room, etc.
•Ventilation of humid exhaust air from indoor pools, bath­rooms, etc.
• General simple ventilation.
System effect
By changing the balance of the supply fan and exhaust fan’s air volumes, the pressure in the room can be balanced freely, and the interrelation with neighboring spaces can be set freely.
As the room is pressurized, the flow of odors and dust, etc., from neighboring areas can be prevented.
The exhaust air is removed from a local position in the room, and dispersion of the stale air can be prevented by applying an entire negative pressure.
Design and construction
properties
•
An ideal design in which the supply air diffuser and exhaust air outlet position relation and air volume, etc., can be set freely is possible.
•A system which adjusts the temperature and humidity of the supply air diffuser flow to the room environment can be incorporated.
•
The supply and exhaust volume can be set freely according to the changes in conditions.
• The position and shape of the supply air diffuser can be set.
• The temperature and humidity of the supply air diffuser flow can be set accordingly, and dust can be removed as required.
•Effective exhausting of dispersed stale air generation sites is possible from a local exhaust air outlet.
•Ventilation in which the air flow is not felt is possible with the supply air diffuser setting method.
Selection points
• Accurate supply air diffuser can be maintained.
• The room pressure balance can be maintained.
• The supply air diffuser temperature and humidity can be adjusted and dust treatment is possible.
• The pressure is positive.
•
The supply air diffuser temperature and humidity can be adjusted, and dust treatment is possible.
•
The positional relation of the exhaust air outlet to the supply air diffuser is important.
• The room pressure is negative.
• Local exhaust is possible.
•Ventilation without dispersing stale air is possible.
•Ventilation with reduced air flow is possible.
•
The positional relation of the exhaust air outlet to the supply air diffuser is important.
Supply air diffuser
Exhaust fan
Exhaust air outlet
Exhaust fan
Exhaust fan
Stale air
Fresh outdoor air
Supply Exhaust Ventilation volume Room pressure
Class 1 Mechanical Mechanical Random (constant) Random
Class 2 Mechanical Natural Random (constant) Positive pressure
Class 3 Natural Mechanical Random (constant) Negative pressure
Class 4 Natural Mechanical & natural Limited (inconstant) Negative pressure
1) System operation with cassette-type air conditioner
2) System operation with ceiling embedded-type air conditioner
3) Independent operation with ceiling suspended-type air conditioner
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CHAPTER 1 ● Ventilation for Healthy Living
3.2 Comparison of ventilation methods
There are two main types of ventilation methods.
Centralized ventilation method
This is mainly used in large buildings, with the fresh outdoor air intake being installed in one machine room. For this method, primary treatment of the fresh outdoor air, such as heat recovery to the intake air and dust removal is performed being distribution to the building by ducts.
Independent zoned ventilation method
This is mainly used in small to medium sized buildings, with areas being ventilated using fresh outdoor air intakes formed of independent ventilation devices. The rate of use of this method has recently increased as independent control is becoming ever more feasible.
Centralized ventilation method Independent zoned ventilation method
Air intake
(fresh out-
door air)
Filters
Air exhaust (stale air)
Cassette-type package air conditioner or fan coil unit
Cassette-type or ceiling suspended-type package air conditioner or fan coil unit
Exhaust grill
Ceiling recessed­type Lossnay
Exhaust air Fresh outdoor air
Finished ceiling
Exhaust air Fresh outdoor air
Finished ceiling
Lossnay
Supply fan
Exhaust
Each unit
Ceiling embedded-type package air conditioner or fan coil unit
Ceiling recessed­type Lossnay
Exhaust grill
Exhaust air Fresh outdoor air
Finished ceiling
Ceiling recessed­type Lossnay
Exhaust grill
Supply grill
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CHAPTER 1 ● Ventilation for Healthy Living
Comparison of centralized ventilation method and independent zoned ventilation method
Centralized ventilation method
The air transfer distance is long thus requiring much fan power.
• Independent equipment room is required.
• Duct space is required.
• Penetration of floors with vertical shaft is not desired in terms of fire prevention.
Generalized per system.
• Design of outer wall is not lost.
• The indoor supply air diffuser and return grille can be selected freely for an appropriate design.
As there are many common-use areas, if the building is a tenant building, an accurate assessment of operating cost is difficult.
• As the usage time setting and ventilation volume control, etc., is performed in a central monitoring room, the user’s needs may not be met appropriately.
•A large amount of ventilation is required even for a few persons.
• An ideal supply air diffuser and return grille position can be selected as the supply air diffuser and return grilles can be laid out freely.
• The only noise in the room is the aerodynamic sound.
• Anti-vibration measures must be taken as the fan in the equipment room is large.
• Centralized management is easy as it can be performed in the equipment room.
• The equipment can be inspected at any time.
• Large as the entire system is affected.
• Immediate inspection can be performed in the equipment room.
Fan power
Installation space
Zoning
Designability
Clarification of costs
Controllability
Comfort
Maintenance and management
Trouble correspondence
Independent zoned ventilation method
As the air transfer distance is short, the fan power is small.
• Independent equipment room is not required.
• Piping space is required only above the ceiling.
Can be utilised for any one area.
• The number of intakes and exhaust air outlets on the outer wall will increase; design must be considered.
• The design will be fixed due to the installation fittings, so the design of the intakes and exhaust air outlets must be considered.
Invoicing for each zone separately is possible, even in a tenant building.
• The user in each zone can operate the ventilator freely.
• The ventilator can be operated even during off­peak hours.
• Consideration must be made of the noise from the main unit.
• Anti-vibration measures are often not required as the unit is compact and the vibration generated can be dispersed.
•Work efficiency is poor as the equipment is not centrally located.
• An individual unit can be inspected only when the room it serves is vacant.
• Limited as only independent units are affected.
• Consultation with the tenant is required prior to inspection of an individual unit.
8
CHAPTER 1 ● Ventilation for Healthy Living

4. Ventilation Performance

The ventilation performance is largely affected by the installation conditions. Ample performance may not be achieved unless the model and usage methods are selected according to the conditions. Generally, the ventilation performance is expressed by “Air volume” and “wind pressure (static pressure)”, and these are necessary when considering ventilation.
4.1 Air volume
Air volume expresses the volume of air exhausted (or supplied) by the unit in a given period. Generally, this is expressed as m
3
/hr (hour).
4.2 Wind pressure
When a piece of paper is placed in front of a fan and let go, the piece of paper will be blown away. The force that blows the paper away is called the wind pressure, and this is normally expressed in units of Pa. The wind pressure is divided into the following three types:
4.2.1 Static pressure
This is the force that presses the surroundings when the air is still such as in an automobile tyre or rubber balloon. For example, in a water gun, the hydraulic pressure increases when pressed by a piston, and if there is a small hole, the water sprays out with force. The pressure of this water is equivalent to the static pressure for air. The higher the pressure is, the further the water (air) can be sprayed.
4.2.2 Dynamic pressure
This expresses the speed at which air flows, and can be thought of as the force at which a typhoon presses against a building.
4.2.3 Total pressure
This is the total force that wind has, and is the sum of the static pressure and dynamic pressure.
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CHAPTER 1 ● Ventilation for Healthy Living
4.3 Measurement of the air volume and wind pressure
Mitsubishi measures the machine’s air volume and wind pressure with a device as shown below according to the Japan Industrial Standards (JIS B 8628).
Measuring device using orifice (JIS B 8628 standards)
Static pressure (
H
)
Air volume (Q)
Measurement method
The unit is operated with the throttle device fully closed. There is no air flow at this time, and the air volume is 0. The maximum point of the static pressure (A point, the static pressure at this point is called the totally closed pressure) can be obtained. Next, the throttle device is gradually opened, the auxiliary fan is operated, and the middle points (points B, C and D) are obtained. Finally, the throttle device is completely opened, and the auxiliary fan is operated until the static pressure in the chamber reaches 0. The maximum point of the air volume (point E, the air volume at this point is called the fully opened air volume) is obtained. The points are connected as shown below, and are expressed as air volume, static pressure curves (Q-H curve).
Connection
Wind dispersing place
Connection
Rectifying
grid
Rectifying
grid
Supply
Air
(SA)
Chamber
Return
Air
(RA)
Rectifying net
Rectifying
net
Wind gauge
duct path
Orifice
Wind gauge
duct path
Orifice
Damper
Blower
Blower
Test unit
Test unit
Static pressure in chamber (Static pressure measurement)
Static pressure in chamber (Static pressure measurement)
Pressure
difference before
and after orifice
(Air volume
measurement)
A) When measuring the supply air volume (with the orifice plate)
B) When measuring the return air volume (with the orifice plate)
10
CHAPTER 1 ● Ventilation for Healthy Living

5. Outdoor Air (ventilation) Load

5.1 How to calculate each approximate load
The outdoor air load can be calculated with the following formula if the required outside air intake volume Q m3/h to be introduced is known:
(Outdoor air load) = γ · Q
F · (iO - iR)
= γ [kg/m
3
] × S [m2] × k × n [person/m2] × Vf [m3/h·person] × (iO - iR): ∆i [kJ/kg]
γ : Specific gravity of air - 1.2 kg/m
3
S:Building’s airconditioned area k:Thermal coefficient; generally 0.7 - 0.8. n:The average population concentration is the inverse of the occupancy area per person. If the number of persons in the
room is unclear, refer to the Floor space per person table below.
Vf : Outdoor air intake volume per person
Refer to the Required outdoor air intake volume per person table below.
i
O : Outdoor air enthalpy - kJ/kg
iR
: Indoor enthalpy - kJ/kg
Floor space per person table (m
2
)
(According to the Japan Federation of Architects and Building Engineers Associations)
Required outdoor air intake volume per person table (m
3
/h·person)
Caution
The application of this table to each type of room should be carefully considered in relation to the degree of smoking in the room.
Office building
Department store, shop
Restaurant
Teatre or
Average Crowded Empty
cinema hall
General design 4 - 7 0.5 - 2 0.5 - 2 5 - 8 1 - 2 0.4 - 0.6
value
5 3.0 1.0 6.0 1.5 0.5
Application example
Required ventilation volume
Degree of smoking
Recommended value Minimum value
Broker’s office
Extremely heavy Newspaper editing room 85 51
Conference room
Quite heavy
Bar
51 42.5
Cabaret
Heavy
Office
25.5
17
Restaurant 20
Light
Shop
25.5 17
Department store
None
Theatre 25.5 17 Hospital room 34 25.5
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CHAPTER 1 ● Ventilation for Healthy Living
Cooling load per unit area
When the volume of outdoor air per person is 25 m
3
/h, and the number of persons per 1 m2is 0.2, the cooling load will be
approximately 157.0 W/m
2
.
How these values are determined can be seen as follows:
● Outdoor air load
Air conditions <Standard design air conditions in Tokyo>
Example calculations of determining ventilation load during both cooling and heating are given as follows:
5.2 Ventilation load during cooling (in general office building)
● Classification of cooling load
(a) is the heat infiltrating the room, and often is 30 to 40% of the entire cooling load. (b) is the heat generated in the room. (c) is applies only when reheating is necessary. (d) is the heat generated when outdoor air is mixed into part of the supply air diffuser volume and introduced into the room. The outdoor air is introduced to provide ventilation for the people in the room, and is referred to as the ventilating load.
Typical load values (during cooling)
Type of load Load
Outdoor air load 53.0 W/m
2
Indoor
People 26.4 W/m
2
generated heat
Lighting equipment 30.0 W/m
2
Indoor infiltration heat 47.6 W/m
2
Total 157.0 W/m
2
Conditions: Middle floor of a general office building facing south.
Class
Heat from walls (q
WS)
(a) Indoor infiltration heat Heat from glass
from direct sunlight (qGS) from conduction & convection (qGS)
Accumulated heat load in walls (q
SS)
Generated heat from people
Sensible heat (q
HS)
(b) Indoor generated heat
Latent heat (qHL)
Genarated heat from electrical equipment
Sensible heat (q
ES
)
Latent heat (q
EL)
(c) Reheating load (q
RL)
(d) Outdoor air load
Sensible heat (q
FS)
Latent heat (qFL
)
}
}
}
}
Dry bulb temp.
Relative humidity
Wet bulb temp. Enthalpy Enthalpy difference
Cooling
Outdoor air 33 °C 63% 27 °C 85 kJ/kg
31.8 kJ/kg
Indoors 26 °C 50% 18.7 °C 53.2 kJ/kg
When the load per floor area of 1 m2with a ventilation volume of 25 m3/h·person is calculated with the above air conditions, the following is obtained:
Outdoor air (ventilation) load = 1.2 kg/m
3
(Specific gravity of air) × 0.2 persons/m2(no. of persons per 1 m2)
× 25 m
3
/h·person (outdoor air volume) × 31.8 kJ/kg (air enthalpy difference indoors/outdoors) = 190.8 kJ/h·m2(530 W/m2)
The Lossnay recuperates approximately 70% of the exhaust air load and saves on approximately 20% of the total load.
Outdoor air
load 33.8%
53.0 W/m
2
Indoor infiltration heat 30.3%
47.6 W/m
2
Indoor
generated heat
(people, lighting
equipment) 35.9%
56.4 W/m
2
156.5 W/m
2
12
CHAPTER 1 ● Ventilation for Healthy Living
● Determining internal heat gain
When classifying loads, the internal heat gain (indoor generated heat + indoor infiltration heat) will be the value of the outdoor air load subtracted from the approximate cooling load when it is assumed that there is no reheating load.
(Internal heat gain)
= 157.0 W/m
2
– 53.0 W/m2= 104.0 W/m
2
●
This value of internal heat gain is based on assumptions for typical loads. To determine individual levels of internal heat gain, the following is suggested:
● Indoor generated heat
(1) Heat generated from people
Heat generation design value per person in office
Sensible heat (SH)= 63.0 W·person Latent heat (LH) = 69.0 W·person Total heat (TH) = 132.0 W·person
The heat generated per 1 m
2
of floor space is
(heat generated from people)
= 132.0 W·person × 0.2 person/m
2
= 26.4 W/m
2
(2) Heat generated from electrical equipment (lighting)
The approximate value of the room illuminance and power for lighting for a general office with illuminance of 300 ­350 Lux, is 20 - 30 W/m
2
.
● Indoor infiltration heat
This is the heat that infiltrates into the building from outside. This can be determined by subtracting the amount of heat generated by people and lighting from the internal heat gain. (Indoor infiltration heat)
= 104.0 – (26.4 + 30.0) = 47.6 W/m
2
The Lossnay recuperates approximately 70% of the outdoor air load and saves on approximately 20% of the total load.
13
CHAPTER 1 ● Ventilation for Healthy Living
5.3 Ventilation load during heating
●
Classification of heating load
Class
Heat lost from walls (q
WS)
(a)
Indoor heat
Heat lost from glass (q
GS)
loss
Heat loss from conduction & convection (q
GS)
Accumulated heat load in walls (q
SS)
(b)
Outdoor air
Sensible heat (q
FS)
load
Latent heat (q
FL)
During heating, the heat generated by people and electrical equipment in the room can be subtracted from the heating load. However, as the warming up time at the start of heating is short, this generated heat may be ignored in some cases.
Percentage of load
Internal heat loss
In terms of load classification, the internal heat loss is the value of the outdoor air load subtracted from the approximate heating load.
Internal heat loss = 133.7 W/m
2
– 56.0 W/m2= 77.7 W/m
2
Heating load per unit area
When the outdoor air volume per person is 25 m
3
/h, and the number of persons per 1 m2is 0.2 persons, the approximate
heating load will be approximately 133.7 W/m
2
.
●
Outdoor air load
Air conditions <Standard design air conditions in Tokyo>
Type of load Load
Outdoor air load 56.0 W/m
2
Internal heat 77.7 W/m
2
Total 133.7 W/m
2
Conditions: Middle floor of a general office building facing south.
Dry bulb temp.
Relative humidity
Wet bulb temp. Enthalpy Enthalpy difference
Heating
Outdoor air 0 °C 50% –3 °C 5.0 kJ/kg
33.5 kJ/kg
Indoors 20 °C 50% 13.7 °C 38.5 kJ/kg
When the load per 1 m2of floor area with a ventilation volume of 25 m3/h·person is calculated with the above air conditions, the following is obtained:
Outdoor air (ventilation) load = 1.2 kg/m
3
× 0.2 persons/m2× 25 m3/h·person × 33.5 kJ/kg = 201.0 kJ/h·m2(56 W/m2)
The Lossnay recuperates approximately 70% of the outdoor air load and saves on approximately 30% of the total load.
Outdoor
air load 41.9%
56.0 W/m
2
Indoor heat loss 58.1%
77.7 W/m
2
133.7 W/m
2

CHAPTER 2
Lossnay Construction and Principle

16
CHAPTER 2 ● Lossnay Construction and Principle

1. Construction and Features of Lossnay

● Lossnay construction
The Lossnay is constructed so that the exhaust air passage from the indoor side to the outdoor side (RA → EA) and the fresh air passage from the outdoor side to the indoor side (OA → SA) cross. The Lossnay heat recovery unit (Lossnay Core) is installed at this cross point, and recovers the heat by conduction through the separating medium between these airflows. This enables the heat loss during exhaust to be greatly reduced.
*RA: Return Air
EA : Exhaust Air OA : Outdoor Air SA : Supply Air
SA (Supply air diffuser)
Supply fan
RA (Return air)
Exhaust side filter
Lossnay Core
Intake side filter
OA (Outdoor air)
Exhaust fan
EA (Exhaust air)
Note: The dust inlet and outlet are linear in the
actual product.
Main Features of Lossnay
(1) Cooling and heating maintenance fees are saved while ventilating.
(2) The capacity and performance of the air conditioner can be reduced.
(3) Dehumidifying during summer, and humidifying during winter is possible.
(4) Comfortable ventilation is possible, (the outdoor air being adjusted to the room temperature.)
(5) Effective sound-proofing.

2. Construction and Principle of Core

● Simple construction
The Lossnay Core is a cross-flow total heat recovery unit constructed of plates and fins made of treated paper. The fresh air and exhaust air passages are totally separated allowing the fresh air to be introduced without mixing with the exhaust air.
●
Principle
The Lossnay Core uses the heat transfer properties and moisture permeability of the treated paper. Total heat (sensible heat plus latent heat) is transferred from the stale exhaust air to the fresh air being introduced into the system when they pass through the Lossnay. Try this simple experiment. Roll a piece of paper into a tube and blow through it. Your hand holding the paper will immediately feel warm. If cold air is blown through the tube, your hand will immediately feel cool. Lossnay is a total heat exchanger that utilizes these special properties of paper.
●
Treated paper
The paper partition plates are treated with special chemicals so that the Lossnay Core is an appropriate heat recovery unit for the ventilator. This paper differs from ordinary paper, and has the following unique properties.
(1) The paper is incombustible and is strong.
(2) The paper has selective hydroscopicity and moisture permeability that permits the passage of water vapor only (including
some water-soluble gases).
(3) The paper has gas barrier properties that does not pass gases such as CO
2.
Hyper Core
The Hyper Core that utilizes the world’s thinnest* 25 µm ultra-thin film imperforate paper has been developed to further reduce gas transfer and to improve humidity exchange efficiency. The Hyper Core is mounted to the LGX-RX
4.
(* As of January 22, 2004, in the case of a high moisture permeable material used for total heat exchange elements)
SA Supply air diffuser (Fresh cold or warm air)
Partition plate (Treated paper)
Spacer plate (Treated paper)
RA Return air (Stale cold or warm air)
Indoors Outdoors
EA Exhaust air (Stale air)
OA Outdoor air (Fresh air)
17
CHAPTER 2 ● Lossnay Construction and Principle
A comparison of the ordinary paper and the Lossnay Core plates is as shown in the table.
Ordinary paper
Water vapor is transferred, but gas elements that are easily dissolved in water such as CO
2
, NO2 are also transferred.
The contaminated air passes through the plates during ventilation and returns to the room.
Treated paper
Water vapor is transferred, but gas elements such as CO
2,
NO
2 are not transferred.
The contaminated air does not almost return to the room when ventilated.
Hyper core
The water vapor transfer rate has increased with further reduction of gas transfer.
The rate at which the contaminated air returns to the room has been reduced to less than 1%*, and the total heat exchange performance has also been improved. (* Based on data measured by Mitsubishi using a single core unit)
Low humid air
Water molecule
25 µm
Gas (CO2) molecule
Non-porous ultra-thin film material
Highly humid air
Highly humid air
Water vapor
Water vapor
CO
2 NO2
CO2 NO2
CO2 NO2Water vapor
Water vapor
Treatment (Selective permeable film) (Incombustible specifications)
Low humid air
Highly humid air
Cellulose fibers
Low humid air
● Total heat recovery mechanism
Sensible heat and latent heat
The heat that enters and leaves in accordance with changing temperature (rise or drop) is called sensible heat. The heat that enters and leaves due to the changes in a matter’s physical properties (evaporation, condensation) is called latent heat.
(1) Temperature (sensible heat) recovery
1) Heat conduction and heat passage is performed through a partition plate from the high temperature to low temperature side.
2) As shown on the right, the heat recovery efficiency is affected by the resistance of the boundary layer, and for the Lossnay there is little difference when compared to materials such as copper or aluminium which also have high thermal conductivity.
Heat resistance coefficients
t1
t2
Ra1
Ra2
Rp
Partition plate Ra1+Ra2
»Rp
Treated paper Cu Al
Ra
1 10 10 10
Rp 1 0.00036 0.0006
Ra
2 10 10 10
Total 21 20.00036 20.0006
(2) Humidity (latent heat) recovery
●
Water vapor is moved through the partition plate from the high humidity to low humidity side by means of the differential pressure in the vapor.
High humidity side
Low humidity side
Partition plate
120µm
18
CHAPTER 2 ● Lossnay Construction and Principle

3. Calculation of the Total Heat Recovery Efficiency

The Lossnay Core’s heat recovery efficiency can be considered using the following three transfer rates:
(1) Temperature (sensible heat) recovery efficiency
(2) Humidity (latent heat) recovery efficiency
(3) Enthalpy (total heat) recovery efficiency
The heat recovery effect can be calculated if two of the above efficiencies is known. (The temperature and enthalpy efficiencies are indicated in the applicable catalogue.)
●
Each recovery efficiency can be calculated with the formulas given below.
●
When the supply air volume and exhaust air volume are equal, the heat recovery efficiencies on the supply and exhaust sides are the same.
●
When the supply air volume and exhaust air volume are not equal, the total heat recovery efficiency is low if the exhaust volume is lower, and high if the exhaust volume is higher. Refer to the Heat Recovery Efficiency Correction Curve in the applicable catalogue for more details.
SA Supply air (Fresh cold or warm air)
RA Return air (Stale cold or warm air)
Indoors Outdoors
EA Exhaust air (Stale air)
OA Outdoor air (Fresh air)
Item Formula
Temperature recovery efficiency (%)
ηt =
t (
OA
) - t (SA)
× 100
t (
OA) - t (RA)
Enthalpy recovery efficiency (%)
ηi =
i (
OA) - i (SA)
× 100
i (
OA
) - i (RA)
η: Efficiency (%)
t: Dry bulb temperature (°C)
i: Enthalpy (kJ/kg)
Calculation of air conditions after passing through Lossnay
If the Lossnay heat recovery efficiency and the conditions of the room and outdoor air are known, the conditions of the air entering the room and the air exhausted outdoors can be determined with the following formulas.
Supply side Exhaust side
Temperature t
SA = tOA - (tOA - tRA) · ηttEA = tRA + (tOA - tRA) · ηt
Enthalpy i
SA = iOA - (iOA - iRA) · ηiiEA = iRA + (iOA - iRA) · ηi
19
CHAPTER 2 ● Lossnay Construction and Principle

4. What is a Psychrometric Chart?

The chart which shows the properties of humid air is called a psychrometric chart. The psychrometric chart can be used to find the (1) Dry bulb temperature, (2) Wet bulb temperature, (3) Absolute humidity, (4) Relative humidity, (5) Dew point and (6) Enthalpy (total heat) of a certain air condition. If two of these values are known beforehand, the other values can be found with this chart. The way that the air will change when it is heated, cooled, humidified or dehumidified can also be seen easily on the chart.
(1) Dry bulb temperature t (°C)
Generally referred to as standard temperature this is measured with a dry bulb thermometer (conventional thermometer). The obtained value is the dry bulb temperature.
(2) Wet bulb temperature t’ (°C)
When a dry bulb thermometer’s heat sensing section is wrapped in a piece of wet gauze and an ample air flow (3 m/s or more) is applied, the heat applied to the wet bulb by the air and the heat of the water vapor that evaporates from the wet bulb will balance at an equal state. The temperature indicated at this time is called the wet bulb temperature.
(3) Absolute humidity x (kg/kg’)
The weight (kg) of the water vapor that corresponds to the weight (kg’) of the dry air in the humid air is called the absolute humidity.
(4) Relative humidity ϕ (%)
The ratio of the water vapor pressure Pw in the humid air and the water vapor pressure Pws in the saturated air at the same temperature is called the relative humidity. This is obtained with the following formula:
ϕR = P
W/PWS × 100
(5) Dew point t” (°C)
The water content in the air will start to condense when air is cooled. The dry bulb temperature at this time is called the dew point.
(6) Enthalpy i (kJ/kg)
Physical matter has a set heat when it is at a certain temperature and state. This retained heat is called the enthalpy, with dry air at 0 °C being set at 0.
Temperature (°C)
Absolute humidity x (kg/kg’)
Wet bulb temperature
(dew point) t’ (°C)
Relative humidity ϕ (%)
The dew point t” of the air at point A is the temperature of the point at the same absolute humidity as point A on the saturation curve.
t” °C dew point
Enthalpy i (kJ/kg)
A
t”
Parallel to absolute temperature scale line
20
CHAPTER 2 ● Lossnay Construction and Principle

5. Calculation of Lossnay Heat Recovery

The following figure shows the conditions of various air states when fresh air is introduced through the Lossnay Core. If a conventional sensible heat recovery unit is used alone and is assumed to have the same heat recovery efficiency as Lossnay, the condition of the air supplied to the room is expressed by point A in the figure. This point shows that the air is very humid in summer and very dry in winter. The air supplied to the room with Lossnay is indicated by point S in the figure. The air is precooled and dehumidified in the summer and preheated and humidified in the winter before it is introduced to the room.
iSA
iOA
tOA tSA
A
S
O
R
i
RA
iSA
iOA
tRA tRA
S
R
AO
t
SA tOA
XOA
XSA
XRA
XRA
XSA
XOA
iRA
The quantity of heat recovered by using the Lossnay Core can be calculated with the following formula.
Total heat recovered: qT = γ · Q · (iOA - iSA) [W]
= γ · Q · (i
OA - iRA) × ηi
Where γ = Specific weight of air under standard conditions 1.2 (kg/m
3
)
Q= Treated air volume (m
3
/h) t= Temperature (°C) x= Absolute humidity (kg/kg’) i= Enthalpy (kJ/kg) η = Heat recovery efficiency (%)
●
Suffix meanings
OA : Outdoor air RA : Return air SA : Supply air
Enthalpy (kJ/kg)
Outdoor air load
Lossnay Core heat recovery
Enthalpy (kJ/kg)
Outdoor air load
Lossnay Core heat recovery
Outdoor air
condition in
winter
Supply air condition of
the Lossnay
Supply air condition of
the Lossnay
Room air
condition
in summer
Outdoor air condition
in summer
Absolute
humidity (kg/kg’)
Room air condition in winter
Dry bulb temperature (°C)

CHAPTER 3
General Technical Considerations

1. Lossnay Heat Recovery Effect

1.1 Comparison of outdoor air load of various ventilators
Examples of formulas to compare the heat recovered and outdoor air load when ventilating with the Lossnay (total heat recovery unit), sensible heat recovery ventilation (sensible HRV) and conventional ventilators are shown below.
(1) Cooling during summer
Conditions
●
Model LGH-100R type
●
Heat recovery efficiency table (%)
(at 50Hz, high speed) (For summer)
●
Ventilation rate: 1000 m3/h (specific gravity of air
ρ
= 1.2 kg/m3)
22
CHAPTER 3 ● General Technical Considerations
Lossnay Sensible HRV
Conventional
ventilator
Temperature
79 79 –
(sensible heat)
Enthalpy
67 19* –
(total heat)
hOA
hSA
hRA
84.6
63.4
52.9
tOA
33
tSA
27.5
tRA
26
R
S
AO
X
OA
0.0201
XSA
0.0140
XRA
0.0105
●
Lossnay (Supply air diffuser temperature)
tSA = 33°C – (33°C – 26°C) × 0.79 = 27.5°C
(Supply air diffuser enthalpy)
hSA = 84.6 – (84.6 – 52.9) × 0.67 = 63.4 kJ/kg
Heat recovered
(84.6 – 63.4) × 1.2 × 1,000 = 25,440 kJ/h = 7.07 kW
Outdoor air load
(63.4 – 52.9) × 1.2 × 1,000 = 12,600 kJ/h = 3.5 kW
●
Sensible HRV (Supply air diffuser temperature)
tSA = 78.9°C – (33°C – 26°C) × 0.79 = 27.5°C
(Supply air diffuser enthalpy)
hSA
= kJ/kg (from psychrometric chart)
Heat recovered
(85.0 – 78.9) × 1.2 × 1,000 = 7,320 kJ/kg = 2.03 kW
Outdoor air load
(78.9 – 53.2) × 1.2 × 1,000 = 30,840 kJ/h = 8.56 kW
[Calculated enthalpy recovery efficiency 2.03 ÷ (2.03 + 8.56) × 100 = 19]
●
Conventional ventilator If a conventional ventilator is used, the heat recovered will be 0 as the supply air diffuser is equal to the outdoor air. The outdoor air load is: (84.6 – 52.9)
×
1.2 ×1,000 = 38,040 kJ/h = 10.6 kW
Calculation example Summer conditions
Absolute humidity (kg/kg’)
Room air condition in summer
Outdoor air condition
in summer
Supply air condition
of the Lossnay
Dry bulb temperature (°C)
Lossnay heat recovery
Outdoor air load
Enthalpy
(kJ/kg)
Supply air
Room air
Air
conditioner
Lossnay Sensible HRV
Conventional
ventilator
Dry bulb temperature
Absolute humidity
Relative humidity
Enthalpy
26°C
27.5 27.5 33
14.0 20.1 20.1
61 86 63
63.4 78.9 84.6
7.1 20.0 0
3.5 8.6 10.6
33 81 100
10.5 g/kg’
50%
52.9 kJ/kg
Outdoor air
Exhaust air
Dry bulb temperature Absolute humidity Relative humidity
Enthalpy
33°C
20.1 g/kg’
63%
84.6 kJ/kg
Dry bulb temperature (°C)
Absolute humidity (g/kg’)
Relative humidity (%)
Enthalpy (kJ/kg)
Outdoor air load (kW)
Outdoor air load ratio (%)
Total heat recovered (kW)
* Calculated volume under below conditions.
(2) Heating during winter
Conditions:
●
Model LGH-100R type
●
Heat recovery efficiency table (%)
(at 50Hz, high speed) (For winter)
●
Ventilation rate: 1000 m3/h (Specific gravity of air
ρ
= 1.2 kg/m3)
23
CHAPTER 3 ● General Technical Considerations
Lossnay Sensible HRV
Conventional
ventilator
Temperature
79 79 –
(sensible heat)
Enthalpy
71 47* –
(total heat)
Supply air
Room air
Air
conditioner
Lossnay Sensible HRV
Conventional
ventilator
Dry bulb temperature
Absolute humidity
Relative humidity
Enthalpy
20°C
15.8 15.8 0
5.1 1.9 1.9
46 17 50
28.7 20.7 4.7
8 5.3 0
3.3 5.9 5.6
29 47 100
7.2 g/kg’
50%
38.5 kJ/kg
Outdoor air
Exhaust air
Dry bulb temperature Absolute humidity Relative humidity
Enthalpy
0°C
1.9 g/kg’
50%
4.7 kJ/kg
Dry bulb temperature (°C)
Absolute humidity (g/kg’)
Relative humidity (%)
Enthalpy (kJ/kg)
Outdoor air load (kW)
Outdoor air load ratio (%)
Total heat recovered (kW)
●
Lossnay (Supply air diffuser temperature) tSA=
(20°C – 0°C) × 0.79 + 0°C = 15.8°C
(Supply air diffuser
enthalpy)
hSA=
(38.5 – 4.7) × 0.71 + 4.7
=
28.7 kJ/kg
Heat recovered (28.7 – 4.7) × 1.2 × 1,000
= 28,800 kJ/h = 8.0 kW
Outdoor air load (38.5 – 28.7) × 1.2 × 1,000
=
11,760 kJ/h = 3.3 kW
●
Sensible HRV (Supply air diffuser temperature) tSA=
(20°C – 0°C) × 0.79 + 0°C = 15.8°C
(Supply air diffuser
enthalpy)
hSA=
20.7 kJ/kg (from psychrometric chart)
Heat recovered (20.7 – 4.7) × 1.2 × 1,000
= 19,200 kJ/h = 5.3 kW
Outdoor air load (38.5 – 20.7) × 1.2 × 1,000
= 21,360 kJ/h = 5.9 kW
[Calculated enthalpy recovery efficiency 5.3 ÷ (5.3 + 5.9) × 100 = 47]
●
Conventional ventilator If a conventional ventilator is used, the supply air diffuser is the same as the outdoor air and the exhaust is the same as the room air. Thus the heat recovered is 0 kcal and the outdoor air load is (38.5 – 4.7) × 1.2 × 1,000 = 40,560 kJ/h = 11.3 kW
Calculation example Winter conditions
hRA
iOA
tOA
0
tSA
15.8
tRA
20
R
S
O
A
X
RA 0.0072
XSA 0.0051
XOA 0.0019
hSA
38.5
4.7
28.7
Absolute humidity (kg/kg’)
Outdoor air
condition in
winter
Room air condition
in winter
Supply air condition
of the Lossnay
Dry bulb temperature (°C)
Lossnay
heat recovery
Outdoor air load
Enthalpy
(kJ/kg)
* Calculated volume under below conditions.
24
CHAPTER 3 ● General Technical Considerations

2. Example Heat Recovery Calculation

(1) Setting of conditions
(Note: Tokyo Power, industrial power 6 kV supply)
●
Return air volume (RA) = 8,000 m3/Hr
●
Outdoor air volume (OA) = 8,000 m3/Hr
●
Air volume ratio (RA/OA) = 1.0
●
Air conditions
(2) Selection of Lossnay model (select from treatment air volume catalogue)
●
Model name: LGH-100RX4 × 8 unit
●
Processing air volume per unit RA = 8,000 m3/Hr, OA = 8,000 m3/Hr, Air volume ratio (RA/OA) = 1.0
●
Heat recovery efficiency : Heat recovery efficiency = 79%, Enthalpy recovery efficiency (cooling) = 67%,
Enthalpy recovery efficiency (heating) = 71%
●
S
tatic pressure loss (unit-type) RA = 100 Pa, OA = 100 Pa (Note: Each motors are High notch)
●
Power consumption (pack-type) = 440W × 8 unit
= 3.52 kW
(3) State of indoor supply air
(4) Outdoor air load and heat recovered
(5) Recovered money (power rates)
Units When Heating When Cooling
Operation time (h/yr)
10h/day × 26 days/mo. × 5 mo./yr. = 1,300 h/yr 10h/day × 26 days/mo. × 4 mo./yr. = 1,040 h/yr
Electricity fee
(yen/kWh)
16.22 17.84
Capacity per
(kW/kW) 3.1 2.6
1 kW of electricity
Energy unit cost
(yen/kWh)
16.22/3.1 = 5.23 17.84/2.6 = 6.86
Season Winter heating Summer cooling
Item
Dry bulb temp
.Wet bulb temp.
Relative humidity
Absolute humidity
Enthalpy h Mark
Dry bulb temp.
Wet bulb temp.
Relative humidity
Absolute humidity
Enthalpy h Mark
DB [°C] WB [°C] RH [%]
× [kg/kg (DA)]
[kJ/kg (DA)]
in page 25 DB [°C] WB [°C] RH [%]
× [kg/kg (DA)]
[kJ/kg (DA)]
in page 25
Outdoors
0 –2.7 50 0.0018 4.7
1
33 27.1 63 0.0202
85.0 (20.3)
3
Indoors 20 13.8 50 0.0072 38.5
2
26 18.7 50 0.0105
53.0 (12.7)
4
Heating Cooling
= { 20 (Indoor temperature) – 0 (outdoor air temperature)} × = 33
(Outdoor air temperature) – { 33 (outdoor air temperature) –
Temperature [°C] 0.79 (heat recovery efficiency) + 0 (outdoor air temperature) 26 (indoor temperature)} × 0.79 (heat recovery efficiency)
= 15.8 = 27.5
Enthalpy
= {38.5 (Indoor enthalpy) – 4.7 (outdoor air enthalpy)} × = 85 (Outdoor air enthalpy) – { 85 (outdoor air enthalpy) –
[kJ/kg (DA)]
0.71 (enthalpy recovery efficiency) + 4.7(outdoor air enthalpy)
53
(indoor enthalpy)} × 0.67 (enthalpy recovery efficiency)
= 28.7 = 63.6
Numerical value obtained •Dry-bulb temperature = 15.8 °C •Wet-bulb temperature = 9.9 °C•Dry-bulb temperature = 27.5 °C •Wet-bulb temperature = 21.8 °C
from above equation and •Relative humidity = 46% •Absolute humidity = 0.005 kg/kg (DA)•Relative humidity = 61% •Absolute humidity = 0.014 kg/kg (DA)
psychometric chart•Enthalpy = 28.7 kJ/kg (DA) (page 25,
5
)
•
Enthalpy = 63.3 kJ/kg (DA) (page 25, 6)
Heating Cooling
Fresh air load without
= 1.2 (Air specific gravity) × 8,000 (outdoor air volume) × = 1.2 (Air specific gravity) × 8,000 (outdoor air volume) ×
Lossnay (q
1)
{ 38.5 (indoor enthalpy) – 4.7 (outdoor air enthalpy) } { 85.0 (outdoor air enthalpy) – 53.2 (indoor enthalpy) }
= 324,480 kJ/h = 90.1 kW = 307,200 kJ/h = 85.3 kW
= 90.1 (Outdoor air load) (q
1) × = 85.3 (Outdoor air load) (q1) ×
Outdoor air load with
{ 1 – 0.71 (enthalpy recovery efficiency)} { 1 – 0.67 (enthalpy recovery efficiency) }
Lossnay (q
2)
= 26.1kW = 28.2 kW
or or
=
Air specific gravity × outdoor air volume × (indoor enthalpy – indoor blow enthalpy)
=
Air specific gravity × outdoor air volume × (indoor enthalpy – indoor blow enthalpy)
= q1 – q2 = q1 – q2 = 90.1 - 26.1 = 85.3 - 28.2
Heat recovered (q
3)
= 64.0 kW = 57.1 kW
or or
= Outdoor air load (q1) × enthalpy recovery efficiency = Outdoor air load (q1) × enthalpy recovery efficiency
•
Outdoor air load = 90.1 kW = 100%
•
Outdoor air load =85.3 kW = 100%
Outdoor air load (%)•Outdoor air load with Lossnay = 26.1 kW = 29%
•
Outdoor air load with Lossnay = 28.2 kW = 33%
•
Heat recovered = 64.0 kW = 71%
•
Heat recovered = 57.1 kW = 67%
Heating Cooling
=
Heat recovered: kW ×Unit price yen/W ×operation time Hr/year = Heat recovered: kW × Unit price yen/W × operation time Hr/year
Yearly saved money = 64.0 kW × 5.23 yen/kWh × (1,300hr/year) = 57.1 kW × 6.86 yen × (1,040hr/year)
= 435,100 yen = 407,374 yen
Remarks If recovered heat is converted to electricity : heating = 64.0 kW/3.1 = 20.6 kW/h cooling = 57.1 kW/2.6 = 22.0 kW/h
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