Handbook of air conditioning and refrigeration / Shan K

9.56 CHAPTER NINE
The following are the EERs indicating the energy use of a hermetic refrigeration compressor
and motor, and the equivalent COP and kW/ton values:
EER is widely used for reciprocating and scroll compressors in air-cooled, direct-expansion refrigeration
systems. The coefficient of performance and kW/ton are usuallly used for water-cooled
centrifugal chillers. They are often rated at different operating conditions. Water-cooled chillers
always show a more energy-efficient index than air-cooled DX systems.
9.21 SAFETY REQUIREMENTS AND MACHINERY ROOM
Refrigerant Safety
Refrigerant hazards stemming from leaks in the pipe joints, the rupture of system components, and the
burning of escaping refrigerant depend on the type of refrigerant, the occupancy classification, and the
refrigeration system. As discussed in Sec. 9.3, refrigerants can be classified into six safety groups that
range from lower toxicity and no flame propagation (safety group A1) to higher toxicity and higher
flammability (safety group B3). The type of occupancy may be one of the following five categories:
● Institutional or health care, such as hospitals and nursing homes
● Public assembly, such as auditoriums and department stores
● Residential, including hotels and apartments
● Commercial, such as offices, restaurants, and markets
● Industrial, such as factories and warehouses
Application Rules for High-Probability Systems
EER COP kW/ton
6 1.758 2.0
8 2.344 1.5
10 2.930 1.2
12 3.516 1.0
15 4.395 0.8
20 5.860 0.6
30 8.790 0.4
A tightly sealed refrigerant system is always necessary to reduce refrigerant leaks that may produce
refrigerant hazards. In addition, limiting the quantity of refrigerant in a refrigeration system per occupied
space, thereby reducing the possible leaks from joints and seals in a high-probability system,
is an effective means of reducing the hazards of refrigerants for the safety of people and property.
ASHRAE Standard 15-1994 specifies a number of rules and requirements for various refrigerants
in high-probability refrigeration systems. These rules are described in the following paragraphs.
1. Any refrigeration system in a room air conditioner or packaged terminal air conditioner
(PTAC), or any small packaged unit for which the refrigerant charge does not exceed 6.6 lb (3 kg),
is considered to meet the system refrigerant safety application requirements.
2. Refrigerants that belong to the A1 safety group (HCFC-22, HFC-134a, etc.) and are used in
high-probability refrigeration systems have the following restrictions: