Master-Bilt Super Controller Operators Manual

Master

Bilt Electronic Superheat Controller Bulletin

5/16 Rev. B 57

02155

Page 1

Application and Installation Bulletin for Master-Bilt® Refrigeration Superheat Controller Kit Assembly(A900-22007), 120/208/240/1/60, R404A, LT/MT APPS

Introduction

The superheat controller is designed to control Master-Bilt made evaporator system to replace the mechanical thermal expansion valve. Each Master-

Refrigeration Superheat Controller Kit contains a Master-Bilt®

Bilt

Superheat Controller, one electric expansion valve, one pressure transducer, one temperature sensor and one 24VAC/40VA, 120/208/240 V primary input transformer.

Since it is a TRUE SUPERHEAT control, the evaporator will achieve the highest possible efficiency. The unique design of the control algorithm also permits the compressor head pressure to be free floated within its operating range with variable ambient temperature. Therefore, the refrigeration system in low ambient condition can achieve the highest possible Energy Efficiency Ratio.

Below Picture 1 shows the basic components in this control kit.

Picture 1. Superheat Controller Kit

Master

Bilt Electronic Superheat Controller Bulletin

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True Superheat Control

Picture 2 below shows us how TRUE SUPERHEAT is measured at a freezer evaporator.

Picture 2

Picture 3 is the control schematic drawing to show us how the Master-

Bilt

electronic superheat controller works.

The suction pressure transducer is mounted at suction line or header to measure the evaporating pressure. The controller stores the P-T chart of Refrigerant R404A and converts the suction pressure into saturated temperature. For example, if the pressure is 15.0 PSIG, the saturated or evaporating temperature is about -22

The suction outlet temperature sensor is mounted on the suction line about 4 to 6” outside the evaporator to measure the superheated vapor temperature. In this

case, if the suction outlet temperature is measured -14

F, the evaporator TRUE

SUPERHEAT is the suction outlet temperature minus the evaporating

temperature, or -14

F –(-22oF) = 8oF.

Master

Bilt Electronic Superheat Controller Bulletin

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Evaporator

Distributor

Liquid Line

Suction

Temp Sensor

Suction Line

Electric

Expansion

Valve

Pressure

Transducer

SUPERHEAT CONTROLLER

MB P/N: 19

14221

Superheat is the measurement of level of liquid refrigerant converted to vapor inside the evaporator tubes by absorbing heat from ambient air. When the superheat is higher than 0 vapor phase completely. If the superheat is less than 0 be some un-vaporized liquid present at the evaporator outlet. This liquid may flood back to compressor and may cause harm.

Therefore, a certain superheat is required to maintain the evaporator working at high efficiency while prevent liquid refrigerant from flooding back to the compressor. Master-Bilt uses typical 10

applications.

Picture 3

F, we say the refrigerant changes from liquid phase to

F superheat for most of its

F or close to it, there will

Master

Bilt Electronic Superheat Controller Bulletin

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When the true superheat is higher than 10oF while in cooling mode, the controller will tell the electric expansion valve open more steps to allow more refrigerant entering to the evaporator. The controller will modulate the electric expansion valve in closing direction when it sees the true superheat is less than the set point of 10 controller operates at fast reaction time and uses PID valve control algorithm.

Floating Head Pressure

In a typical Master-Bilt pressure of a condensing unit is allowed to be freely floating. The compressor will work at less head pressure and less input power while output more cooling capacity at low ambient temperature. This is to say the system of floating head pressure will save more energy than the system with head pressure control valve where a typical head pressure limit is set at 225 PSIG. For example, a Copeland ZF13 Scroll compressor working at -20

The typical mechanical head pressure set point: 225 PSIG Outdoor condenser design TD (Condensing Temperature – Ambient Temperature): 20

F. The evaporator works at the highest possible efficiency since the

Master Controller refrigeration system, the head

F suction temperature:

At 50

F ambient temperature, the condensing unit with head pressure control

valve:

Evap Temp (F) = -20 Suct Press (PSIG) = 16 Cond Temp (F) = 97 Head Press (PSIG) = 225 Cooling Capacity (BTUH) = 15700 Power (Watts) = 2670 Current (Amps) = 8.6 Mass Flow (lbs/hr) = 268 EER (BTUH/W) = 5.9

At 50oF ambient temperature, the condensing unit without head pressure control valve:

Evap Temp (F) = -20 Suct Press (PSIG) = 16 Cond Temp (F) = 70 Head Press (PSIG) = 148 Cooling Capacity (BTUH) = 18900 Power (Watts) = 2100 Current (Amps) = 7.4 Mass Flow (lbs/hr) = 276 EER (BTUH/W) = 9

Master

Bilt Electronic Superheat Controller Bulletin

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For a freezer requiring 15700 BTUH at 18 Hour Compressor Runtime, the energy consumption is equal to Power x Runtime = 2.67 KW x 18 H = 48.06 KWH per day.

When the condensing unit without head pressure control valve is used for this same freezer, the compressor runtime will be = (15700/18900) x 18H = 14.95 H. The energy consumption is equal to Power x Runtime = 2.1 KW x 14.95 H =

31.40

KWH per day.

Therefore, total of 48.06 – 31.40 = 16.66 KWH energy is saved per day. Consider $0.10 per KWH energy cost, then 365 days x 16.66 KWH/Day x $0.10 /KWH = $608.09 saving per year.

The average daily temperature of Year 2009 in Chicago: 48.6 The average daily temperature of Year 2009 in Denver: 49.1 The average daily temperature of Year 2009 in Boston: 50.3

For a refrigeration system with free floating head pressure, it saves energy when

the ambient temperature is lower than 77

For further detailed calculation of how much energy is to be saved, please consult Master-Bilt engineering for Bin Analysis Energy Savings.

Summary of Benefits of Master-Bilt Electronic Superheat Control

 Significant energy savings from reduced head pressure in low ambient

conditions.

 Energy savings from high efficient evaporator operation.  Fast pulldown  Closer temperature control  Extended product life --- Shelf life and compressor life expectancy  Short ROI

Picture 4 indicates the comparison of pull times of a system between superheat control of EEV and regular mechanical control of TEV.

A typical Sporlan SER-6, or rated 6 ton electric expansion valve, can cover most of applications from 1/2 to 6 ton evaporators.

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