Chilling statistics | Archive Titles

Table 1: pilot system’s recorded and design performance

High side	Actual	Design
Copeland ZB45KCE-TFD x 2 R404 circuit
Temperature (condenser)	36°C	36°C
Temperature (evaporator)	-15°C	-15°C
Cooling load	17.8kW	15.0kW
Power input (R404a compressed)	7.0kW	8.0kW
Power input (condenser fans)	0.5kW	1.7kW
Total heat of rejection	24.8kW	23.0kW
Coefficient of performance	2.39	1.5

Medium temperature CO2 circuit

Temperature (evaporator)	-10°C	-10°C
Cooling load	4.7kW	4.7kW
Power input (pump)	0.8kW	1.0kW
Coefficient of performance	5.7	4.7

Low temperature CO2 circuit

Bitzer 2KC-3.2 K
Temperature (condenser)	-10°C	-10°C
Temperature (evaporator)	-28°C	-28°C
Cooling load	10.0kW	10.0kW
Power input (CO2)	1.8kW	1.5kW
Total power input	11.8	11.5
Coefficient of performance	5.6	6.7

TOTAL SYSTEM

Power (total)	10.1kW	12.2kW
COP	1.5	1.2

Table 2: Tewi comparison of standard and natural cascade systems
System and period of assessment	CO2
Standard R-404a system, Tewi 1 year	1310.8 tonnes
Cascade system, Tewi 1 year	536.7 tonnes
Difference between systems over 1 year	774.2 tonnes
Standard R-404a system, Tewi 10 year	13108.4 tonnes
Cascade system, Tewi 10 year	5366.8 tonnes
Difference between systems over 10 year	7741.5 tonnes
Based on 61% run time. Tewi %3D total equivalent warming impact