The coefficient of performance of a refrigerator working on a reversed Carnot cycle is 4. The  ratio of the highest absolute temperature to the lowest temperature is:

A Carnot refrigerator requires 1.5 kW / ton of refrigeration to maintain a region at a temperature  of -30 ^OC, the COP of the Carnot refrigerator is : 

In the given figure, E is a heat engine with efficiency of 0.4 and R is a refrigerator. Given that Q₂+Q₄=3Q_1,  the COP of the refrigerator:

S

One ton refrigeration is equivalent to:

A Carnot refrigerator has a COP of 6. What is the ratio of the lower to the higher absolute temperatures?

When the lower temperature is fixed. COP of a refrigerating machine can be improve by:

A refrigeration plant working on Carnot cycle is designed to take the load of 4T of refrigeration. The cycle works between 2⁰C and 27⁰C. The power required to run the system is:

In the system given below, the temperature T = 300 K. The thermodynamic efficiency of engine E equals to the reciprocal of the COP of R, if_______

In a vapour compression refrigeration plant, the enthalpy values at different points are:

(i) Enthalpy at exit of the evaporator = 350kJ/kg

(ii) Enthalpy at exit of the compressor = 375kJ/kg

(iii) Enthalpy at exit of the condenser = 225 kJ/kg

The refrigerating efficiency of the plant is 0.8. What is the power required per kW of cooling to be produced?

The values of enthalpy at the beginning of compression, at the end of compression and at the end of condition are 185 kJ/kg, 210kJ/kg and 85 kJ/kg respectively. What is the value of the COP of the vapour compression refrigeration system?

Air cooling is used for Freon compressors whereas water jacketing is adopted for cooling ammonia compressors. This is because

In vapour compression refrigeration plant, the refrigerant leaves the evaporator at 195 kJ/kg and the condenser at 65 kJ/kg. For 1 kg/s of refrigerant, what is the refrigeration effect?

Vapour  compression refrigeration system cannot be used to produce ultralow temperatures because

Assertion (A): In vapour compression refrigeration system throttle valve is used and not expansion cylinder.

Reason (A): Throttling is a constant enthalpy process. 

A refrigerating system operating on reversed Brayton  cycle is used for maintaining 250K. if the temperature at the end of constant pressure cooling is 300 K and rise in the temperature of air in the refrigerator is 50 K then the net work of compression will be (assume air as the working substance with c_p  = 1kJ per kg per ⁰C )

The operating temperature of a cold storage is – 2⁰ C. Heat leakage from the surrounding is 30 kW for the ambient temperature of 40⁰ C .The actual COP of the refrigeration plant used is one fourth that of an ideal plant working between the same temperatures. The power required to drive the plant is:

Thermoelectric refrigeration system is based on-

Horse power and KW required per tons of refrigeration is expressed as-

A capillary tube is employed in a refrigeration cycle to

Sub-cooling in a refrigeration cycle

The thermodynamic cycle used in aircraft refrigeration is-

In absorption refrigeration cycle, the compressor of the vapor compression refrigeration  cycle is replaced by-

Absorption system normally uses the following refrigerant-

The refrigerant used for absorption refrigerators working from solar collectors is a mixture of water and-

An Electrolux refrigerator uses-