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Low-Global-Warming Chemicals and Refrigerant Technologies
Environmental and
Thermal Engineering Lab Description
APB's Laboratory has the capability to test several types of refrigeration
equipment with various refrigerants. Refrigeration compressors are tested
according to the ANSI/ASHRAE 23-1993 Test Standard and under various operating
conditions. Household refrigerator/freezers are tested according to ANSI/AHAM
HRF-1-1988 Energy Consumption Test Standard and under other conditions. This
laboratory has the capability to test foreign manufactured refrigerator/freezers
that have various electrical voltages and frequencies. Commercial refrigerated
display cases are tested according to the ANSI/ASHRAE 72-1983 Test Standard
as well as other conditions.
Two 576 ft3 environmental chambers and one 2,128 ft3 chamber control the ambient conditions under which the refrigerator/freezers and supermarket display cases are tested. The temperature range of the chambers is 60 to 120°F, and the relative humidity ranges from 30 to 95%. Computerized data acquisition systems are used for testing the equipment in the chambers.
Machine shop, electronic shop, instrument calibration, and quality assurance services are available on-site. A few selected examples of the the use of the general facilities follow.
Secondary Loop System
A secondary loop system has been designed to investigate the performance of
secondary fluids and primary refrigerants in a refrigeration system which
incorporates a secondary fluid loop to provide the refrigeration from the
vapor compression cycle to supermarket cases. Tests are planned to measure
the cooling delivered and the energy required for various secondary fluids.
Options to reduce energy consumption include the use of natural refrigerants
(e.g., ammonia) or zeotropes as the primary refrigerant. Other investigations
may include designs and controls to provide the various refrigerating temperatures
needed in a supermarket at the lowest energy consumption.
Additional Supermarket
Refrigeration
With regard to future systems, the use of secondary loops to provide retail
food refrigeration has been investigated. This design allows the use of refrigerants
which are mildly toxic or flammable by isolating the refrigerant in an equipment
room and transferring the refrigeration to the store equipment via a secondary
fluid. One project with the University of Wisconsin identified the losses
associated with implementing a secondary loop system in order to evaluate
the potential for improving the performance to minimize these losses and to
make the technology competitive. Another project at the University of Illinois
investigated fluids and heat exchanger designs for fluids which can be successfully
implemented in display cases used for the low-temperature conditions of ice
cream and frozen foods. Appropriate defrost strategies for these types of
cases were also evaluated.
Household Refrigerator/Freezer
APB has conducted testing of alternative refrigerants and
unconventional systems for household refrigerator/freezers. Testing
included the evaluation of new chemicals developed through the EPA new
chemicals program and of hydrocarbon mixtures. The layout of the test
chamber and the placement of test refrigerator/freezers are shown in
this picture. Two unconventional
refrigerator/freezers were studied: a two-evaporator system that takes
advantage of the temperature glide of zeotropic refrigerants and a
two-circuit system that enables tailoring refrigerants to freezer and
fresh food compartments.
