Lochinvar SCH065 User Manual

Getting Started

with Solar

Design Professional:

Lochinvar is very proud to present you with our Lochinvar TiSUN Commercial Solar Thermal Systems catalog
and want to thank you for your interest in our products.

We fully understand that in today’s engineering climate, it is difficult to know and incorporate every detail

and nuance in high performance HVAC and Radiant Systems. We are experts in the field of water heating
and now offer our expertise in solar heating technologies and how to incorporate them into new and
existing systems.

Our ability to provide comprehensive solar thermal design support and integration with our premium water
heating products ushers in a new level of professionalism not previously witnessed in the industry.

We invite you to partner with Lochinvar and allow us to be your resource for solar thermal system
knowledge, system sizing and design. We welcome you to contact us for any support that we can provide
you and look forward to the future ahead of us as we design and install green building strategies into your
customer’s facilities.

Thank you for your support.

Best Regards,

Lochinvar Corporation

Figure 1

Solar Thermal System Overview

The basics of a solar thermal system are very straight forward. We use a solar thermal
flat plate collector to harvest the sun’s energy. We transfer the solar thermal energy
into a dedicated pre-heat tank or heat exchanger for maximum efficiencies.

Major Components

A solar thermal domestic water system consists of a
collector, pump, differential controller, heat exchanger, expansion tank,
air management, and tank storage. Although this sounds like quite a
few components, the components found in a forced circulation solar
thermal system are identical to those in a closed loop heating system.

A properly designed solar thermal system will strive to find the proper
balance of collector square footage and storage volume so that the

system will operate at the highest efficiency and provide the quickest

return on investment (ROI).

After collector and storage have been selected, responsibly incorporating the other key components
ensures years of trouble free service. Proper pump sizing and flow, placement and sizing of an expansion
tank, as well as sensors will all enhance the performance of the core group of components.

Collectors

At the heart of every Lochinvar-TiSUN system is a solar thermal flat plate collector. Lochinvar-TiSUN
collectors are constructed with performance and durability in mind. All collectors offered by Lochinvar
bear the OG100 certification by the SRCC (see Figure 1). This certification lists the performance test data
as well as materials used to construct the collector.

Pump Stations

Solar Pump Stations integrate several necessary solar components on a single

chassis. This includes pump, differential controller, safety group (to include the

relief valve), and a place to connect an expansion tank. As an added bonus,

Lochinvar-TiSUN pump stations include an integral flow meter. This pre-packaged

system performs all monitoring of tanks and collector temperatures as well as Btu

metering.

Solar Control

Integral to the pump station is the differential controller. This control can be purchased
separately and paired with the supplied sensors and field supplied circulators to operate a
variety of systems. The included SD card can perform data logging functions as well as gives the
installer the ability to pre-program the control prior to installation at the job site. Our
differential controller also has a slow-start feature that avoids pump pulsing which is beneficial
on days that are overcast.

Solar Storage

When designing a solar thermal system, one thing needs to be kept in mind. The sun does not shine 24­hours a day. Solar storage in commercial solar thermal systems is the key to maximizing the allowable

harvested Btu’s of energy that can be collected from the sun versus Btu’s that will have to be purchased

from the local utility supplier. When designing storage into a system, there are several possibilities for
transferring and storing this energy in the system.

o External heat exchanger w/tank
o Internal heat exchanger in tank
o Solar Hot Water Generator
o Stratified Tanks

Each of these strategies is explained in detail in the section titled, “How to Interface Systems”.

System Accessories

It has been said that, “the devil is in the details”. The performance and installation of a solar thermal

system can be detailed and enhanced with the proper use of solar accessories. It will be very common
for these items to be designed and incorporated into our systems.

System Accessories (continued)

Balancing Valve - In large systems with multiple arrays, supply and return piping
can be simplified by using a balancing valve. The ability to reference flow visually
with our balance valves greatly simplifies the process. (See accessories tab)

Solar Anti-Stagnation Air-Vent - Large systems contain large amounts of air. Initial fill and
purge can be very time consuming if these vents are not included. These vents differ from
normal hydronic air vents in that they recognize temperature as a variable. If a collector array
is in stagnation and fluid is evacuated out of the collector, a simple non-solar specific air-vent
will evacuate steam and create system pressure losses. Our solar-specific air vent will not allow
this to happen; it senses fluid temperatures over 212°F and stops the valve from being able to
vent. (See accessories tab)

Solar Glycol - High temp propylene glycol is specifically suited to solar applications
and with a higher working pressure of forced circulation systems, the boiling point
will be significantly higher, reducing the potential for the glycol to stagnate and
breakdown. (See accessories tab)

Expansion Tanks -Sized according to system volume, expansion tanks are offered from 5
gallons up to 132-gallons and multiple tanks can be “banked” to accommodate system
expansion. (See accessories tab)

Piping a Forced Circulation System

As mentioned earlier, forced circulation is the solar version of a closed loop system complete with air­separation, expansion tank, and circulator. This pressurized system also features a collector,
differential controller, storage tank, and usually some form of boiler or water heater backup. The
differential control unit will monitor the sensor at the tank as well as the sensor at the collector. To
ensure proper operation, we place a sensor in the flow stream of the collector to accurately measure
fluid temperature. There is an additional sensor placed in a bulb well inserted into the solar storage
tank. These sensors will communicate with the differential controller integrated within our pump
station. As long as the tank temperature is below the control set point and the fluid temperature in
the collector is higher than the tank set point, the pump will turn on and start harvesting the suns
energy. When the tank is satisfied the pump simply shuts off.

Why Forced Circulation Systems Are Beneficial

Forced circulation systems are typically charged between 50 to 60 psi with 100% water. When freeze
protection is required, an appropriate mix of propylene-glycol is used. This pressurized system permits
systems to be installed in any climate and provides very wide parameters for supply and return piping.
Proper expansion tank sizing accounts for thermal expansion in closed systems and this is especially
important as the system will see larger temperature differences and higher working temperatures and
pressures. As a DHW load is satisfied and the tank is fully charged with Btu’s, the potential to enter
stagnation is great. As system fluid flashes to steam, the system is equipped to handle the additional
volume. A drain-back system that is not in operation has no fluid in the collector. When a demand is

present, the circulator must fill the system slowly, usually taking a few minutes. On overcast days or days

Figure 3

with sporadic periods of sun, this will prolong delays in valuable harvesting time. Drain-back systems usually
settle for checking the temperature at the absorber or the system piping as opposed to the flow stream.
Accuracy in temperature sensing is vital for proper loading of storage tanks as well as maximizing harvesting
of Btu’s at the collector. Another premium design difference with forced circulation is in the amount of
equipment necessary. No additional tanks or special piping are needed as with a drain-back system.
Systems designed by Lochinvar will feature working temperatures up to 248°F allowing a wide range of solar
harvesting potential. Forced circulation offers versatility in installation, economy, freeze protection, and no
limitation in job size and scale.

Integrating Solar into HVAC and DHW systems

The ability to transfer the sun’s energy into hot water is a very simple process. Transferring it into usable
DHW can be equally as simple. What is the most economical and practical way to do this? Use the solar
thermal energy to pre-heat all incoming cold water. This offers versatility in product selection as well as
efficiency in transferring harvested energy to the Btu hungry incoming water. As the solar preheated water
exits the solar storage tank, it goes on to enter the inlet of the water heater where the temperature can be
raised to its desired temperature. Don’t let the pre-heat term fool you. Lochinvar-TiSUN systems can safely
load the tanks to their maximum temperatures up to 194°F. This preheated fluid will sustain long off times
as the selected storage volume is properly mixed via an anti-scald mixing valve.

How to Interface Systems

Interfacing a solar thermal system to a new or existing domestic hot water system is a simple process. How
do we join two systems while including the previously mention pre-heat strategy? By use of a heat
exchanger placed on the solar loop. Lochinvar offers four simple, but highly effective heat exchanging
components for this process.

Lochinvar’s line of Squire SIT and SDT single and dual coil indirect water heaters.

These tanks feature an integral coil dedicated to solar loop water and readily transfers this heat to
the incoming cold water. Squire tanks are available in models from 30 to 119 gallons.

Brazed plate heat-exchangers coupled with Lochinvar’s Lock-Temp Glass Lined Storage
Tanks can be interfaced with the solar loop to offer flexibility of solar storage in
whatever size tank the project requires. Lock-Temp Tanks can be custom built in
capacities as large as 5,000-gallons and designed to your specification including
custom jacketing and insulation, tappings, sensor wells, etc.

Hot-Water Generator and Tube Bundle
10 standard sizes of tank (from 200 to 940 gallons) and tube bundles have been identified as
standard offerings but Lochinvar can also build a custom tank for your project with an
appropriately sized tube bundle. This system is especially suited for projects that require
double-wall containment.

Soon to be introduced to the Lochinvar Solar Team are a line of stratified solar storage tanks.
This patented TiSUN and proven technology uses the principles of natural stratification to
harvest solar energy. An externally mounted spherical heat exchanger contains a dedicated

copper coil heat exchanger specifically sized to accept solar thermal energy. The spherical heat exchanger is

Figure 2

Solar pre-heat
transferred to the
hot water generator
which feeds a Lock­Temp Tank with an
Armor Water Heater
back-up heat source

Solar pre-heat
transferred to the
Squire SIT Indirect
which feeds Shield
Water Heater

Figure 3

attached to an appropriately sized tank to process the sun’s energy. Four flanged connections, in a strategic
vertical arrangement, allow convective stratification without the use of a circulator. The domestic hot water
version of the tank functions as a reverse indirect that houses a large diameter corrugated stainless steel
coil. High tank temperatures with the natural stratification and direct boiler back up ensures that large
domestic loads can be satisfied. The water heating only version of this tank is configured the same but does
not offer the integral coil for domestic water. These tanks can be used for domestic production but these
loads would need to be handled via a Squire Indirect Water Heater or external brazed-plate heat-exchanger.
Both designs will provide tremendous value for solar thermal projects, especially when mechanical room
space is at a premium.

Designing Solar Thermal Systems

Figure 4

Proper design is centered on finding the proper balance of storage and collector space with the byproduct
being the solar fraction, or percentage of total load to be supplied by solar. To achieve this, we must know
several things. Topping the list by importance, we need to know the total Gallons Per Day load, location,
type of roof, existing storage and water heating btu/h and efficiency. We also need to know how much roof
space is available, the roof pitch, as well as the amount of available space in the mechanical room. We use
these values and input them into the software that we use to run simulations. The simulation takes all of
this information and compiles it into a working system. When this system is designed, the software
processes the simulation based on 365 days of the year and the previous 15 years of weather data for that
location. After simulation, several reports can be printed that validates the selected storage, collector, and
water heating back up. At this point you will also see the solar fraction that all of the equipment will be able
to provide. If this fraction is lower than expected, we can edit the design and add more collector square
footage or more storage, which ever offers a more cost effective design. If this fraction is too high, then we
can reduce the amount or storage and/or collector space and re-run the simulation until the desired fraction
is achieved. Generally speaking, we are looking for a 40° tilt angle. Figure 4 illustrates the system with a

32.3% solar fraction.

Simulation Reports

The simulation report will verify the Lochinvar equipment selected which makes it even easier to
specify. The performance of the Lochinvar product lines with Shield, Armor, Knight, Copper-Fin, SYNC,
and Crest can all be simulated within the software making it easy to dial in the level of performance and
efficiency for an entire system. The solar fraction is truly a dynamic number and mixing and matching
collectors, storage, and boiler or water heater back up can be explored and validated through these
designs and reports.

(See Figure 5)

A very important part of the design process is focused on collector performance and what better way to

Figure 5

Figure 6

measure that performance than an actual picture of collector temperatures. (See Figure 6) This simple
unassuming graph verifies beyond the shadow of a doubt that adequate storage is paired with the proper
balance of collector square footage. In unbalanced and disproportionate systems, these collector performance
temperatures would consistently be above 300°F and put the system into over-temp conditions called
stagnation.

System Assembly

Example: System 5

Two Collector Arrays with Sensors
Single Tank with Sensor
Two Pumps for Collector

Prioritization

Roof Attachment

Knowing the type of roof is very important when mounting a solar thermal collector. A
typical flat membrane roof can readily support the engineered mounting system for
collectors. After the roof is penetrated and properly sealed, the horizontal aluminum bars
are ready to be mounted.

Substructure, Angle Kit, & Collector

Each collector size has a pre-selected number of angle kits that are then placed on the
horizontal bars. The pre-assembled angle kits bolt together and are then ready for 3
horizontal U-channels. (SCH Only) This provides a stable and wind-ready base on which to
place the collector. The collector is then lifted into place and is secured with the supplied
hardware.

Hydraulic Connection, Hydraulic Expansion

Two SCH and up to Six SLV/SLH collectors can be joined to form a single array. This is
completed with the supplied hydraulic expansion kits. The arrays are then fitted with a
hydraulic connection kit that comes with the necessary plug and bulb well for the array. The
array is then ready to be piped to the systems supply and return piping. Piping is to be
Stainless Steel Corrugated Tube (SSCT) rated for solar or brazed copper tube. ProPress®
fittings may be used if the high temp (FKM) seal is used.

Solar System Start up

System Fill & Purging

Programming the Control

After the system has been pressurized, it is now ready for operation. Placing the system into
operation is now a very simple process. Select your system type from a visual guide on the screen,
indicating the arrangement of solar panels, number of tanks, types of pumps used and what the
outputs will be controlling such as mixing valves. A menu of pre-set solar templates has been
created for ease of start up. This variety of templates will quickly guide you through the appropriate
parameters so that the end user is ready for years of efficient solar energy harvesting.

The initial fill and purge of a solar thermal system is similar to that of a closed-loop hydronic
system. Filling the system while removing air and sediment will enhance system performance
from day one. After the system is filled, continue to let the fill/purge pump flow through the
system piping to assist in removing minor particulate and to allow time to remove air. After
sufficient time has passed, allow the system pressure to rise to 60psi. Lochinvar offers different
options for the pump required to perform the system fill & purge.

Other Resources

The balance of our catalog is a resource filled with product literature, specifications, manuals, marketing tools, wtc.
We also offer additional information such as product submittals, jobsite photos, case studies, and other useful tools
on our website at www.Lochinvar.com

We want you to know that Lochinvar is here to help you through your projects and that we are only an e-mail or
phone call away. Feel free to contact us if we can e of any assistance to you.

Lochinvar Customer Service 615-889-8900

Lochinvar Technical support 1-800-722-2101

E-mail our Solar Team [e-mail]

Lochinvar’s local representative in your area will also be glad to help you. For your convenience, we have a rep

locator tool on the front page of our website.

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