Question

In: Physics

A normal refrigeration cycle uses one coolant, so why does vapor compression cycle of an ice...

A normal refrigeration cycle uses one coolant, so why does vapor compression cycle of an ice rink you a primary coolant and a secondary coolant?

Solutions

Expert Solution

The reason is a kind of a politically related technicality.

In fact, some ice rinks used to have a direct cooling by a single coolant. They may have operated at higher temperatures and achieved higher pressures as well as higher efficiencies. See the fourth paragraph of this document.

However, when one looks what the most appropriate coolant is in such systems, he finds out that it's really either ammonia or R-22. The latter causes ozone depletion at 20 times lower rates than other ozone-depleting compounds but even this small amount is unacceptable. On the other hand, R-22 is a 2,000 times more efficient greenhouse gas than CO2 which some people also care about. Due to a combination of building codes, emissions regulations to fight ozone and global warming, and fire regulations, direct coolants ammonia and R-22 are no longer kosher.

There don't seem to be good enough alternatives for direct cooling


Related Solutions

There is a vapor compression type refrigeration cycle using the refrigerant HFC 134 a. In the...
There is a vapor compression type refrigeration cycle using the refrigerant HFC 134 a. In the condenser, it is isostatically cooled, the condensation temperature is 50 ° C., and the condenser outlet is the compressed liquid at 45 ° C. In the evaporator, it is isothermally heated, the evaporation temperature is 10 ° C. and the outlet of the evaporator is heated steam at 15 ° C. When the expansion valve performs isenthalpic expansion, and the adiabatic efficiency of the...
A vapor-compression refrigeration cycle working with R22 contains a liquid-to-suction heat exchanger.
A vapor-compression refrigeration cycle working with R22 contains a liquid-to-suction heat exchanger. The saturated liquid refrigerant at 40 ℃ leaving the condenser and enteringthe heat exchanger is used to superheat the saturated vapor refrigerant leaving the evaporator at 7 ℃ by 8 ℃. If the compressor is capable of pumping 5 1/s of vapor refrigerant measuredat the inlet to the compressor and the compression processes are considered isentropic in both cases listed below, determine; (a) The refrigerating capacity in kW,...
An ideal vapor compression refrigeration cycle using r134a as the refrigerant is being used to cool...
An ideal vapor compression refrigeration cycle using r134a as the refrigerant is being used to cool a house. It provides 3 refrigeration tons ≈ 10.5kW of cooling (heat removal from the house air). The refrigerant in the evaporator operates at 400kPa while in the condenser it is at 1000kPa. Treat the surroundings as a thermal reservoir at 33◦C and the air in the house as a thermal reservoir at 19◦C. All reservoirs are at 100kPa. 1. What is the COPr...
An ideal vapor compression refrigeration cycle with R134a as the working fluid operates between the pressure...
An ideal vapor compression refrigeration cycle with R134a as the working fluid operates between the pressure limits of 200 kPa and 1200 kPa. Determine a) the mass fraction of the refrigerant that is in the liquid phase at the inlet of the evaporator, and b) the amount of heat transfer (in kJ/kg) to the refrigerant in the evaporator (??).
An ideal vapor-compression refrigeration cycle is modified to include a counterflow heat exchanger, as shown in...
An ideal vapor-compression refrigeration cycle is modified to include a counterflow heat exchanger, as shown in the figure below. Ammonia leaves the evaporator as saturated vapor at 1 bar and is heated at constant pressure to 5°C before entering the compressor. Following isentropic compression to 18 bar, the refrigerant passes through the condenser, exiting at 40°C, 18 bar. The liquid then passes through the heat exchanger, entering the expansion valve at 18 bar. If the mass flow rate of refrigerant...
A vapor-compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid. Saturated...
A vapor-compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid. Saturated vapor enters the compressor at 2 bar, and saturated liquid exits the condenser at 10 bar. The isentropic compressor efficiency is 80%. The mass flow rate of refrigerant is 7 kg/min. Determine: (a) the compressor power, in kW. (b) the refrigeration capacity, in tons. (c) the coefficient of performance.
value of y is _____4_______. Consider an ideal vapor-compression refrigeration cycle using Freon 410A (see ....
value of y is _____4_______. Consider an ideal vapor-compression refrigeration cycle using Freon 410A (see . https://www.freon.com/en-/media/files/freon/freon-410a-si-thermodynamic-properties.pdf) The pressure in the evaporator is 10y kPa (That is, if y = 3 the evaporator pressure is 30 kPa). and the temperature at the exit of the condenser is 40oC. The mass flow in the system is (0.05 + y/200) kg/s.   (That is, if y =3, then the mass flow is 0.0.065 kg/s). Find the enthalpy at the entrance to the compressor.        ...
A vapor-compression refrigeration cycle working with R22 contains a liquid-to-suction heat exchanger. The saturated liquid refrigerant...
A vapor-compression refrigeration cycle working with R22 contains a liquid-to-suction heat exchanger. The saturated liquid refrigerant at 40 °C leaving the condenser and entering the heat exchanger is used to superheat the saturated vapor refrigerant leaving the evaporator at 7 °C by 8 °C. If the compressor is capable of pumping 5 l/s of vapor refrigerant measured at the inlet to the compressor and the compression processes are considered isentropic in both cases listed below, determine; (a) The refrigerating capacity...
Q/ A vapor-compression refrigeration cycle working with R22 contains a liquid-to-suction heat exchanger. The saturated liquid...
Q/ A vapor-compression refrigeration cycle working with R22 contains a liquid-to-suction heat exchanger. The saturated liquid refrigerant at 40 °C leaving the condenser and entering the heat exchanger is used to superheat the saturated vapor refrigerant leaving the evaporator at 7 °C by 8 °C. If the compressor is capable of pumping 5 l/s of vapor refrigerant measured at the inlet to the compressor and the compression processes are considered isentropic in both cases listed below, determine; (a) The refrigerating...
This question about " Electro-Mechanical Sysrems: Simple vapor compression cycle" A simple vapor compression cycle works...
This question about " Electro-Mechanical Sysrems: Simple vapor compression cycle" A simple vapor compression cycle works in a residential refrigerator and uses R-410a as a refrigerant. The evaporator temperature is − 20 ºC and the condenser temperature is 35ºC. Saturated vapor enters the compressor. If the refrigerant flow rate is 0.15 kg/s, calculate: - Compressor power - Rejected heat from condenser - The COP of the cycle - The increase in COP if an internal heat exchanger is used that...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT