The refrigerant for a refrigerator should have (a) high sensible heat (b) high total heat (c) high latent heat (d) low latent heat

1 Answer

Answer :

Ans: c

Related questions

Description : Choose the correct statement (a) A refrigerant should have low latent heat (b) If operating temperature of system is low, then refrigerant with low boiling point should be used (c) Pre-cooling and sub-cooling bf refrigerant are same (d) Superheat and sensible heat of a. refrigerant are same

Last Answer : Ans: b

Description : Which of the following is not a desirable property of a refrigerant (a) highmisibility with oil (b) low boiling point (c) good electrical conductor (d) large latent heat

Last Answer : Ans: c

Description : At lower temperatures and pressures, the latent heat of vaporization of a refrigerant (a) decreases (b) increases (c) remains same (d) depends on other factors

Last Answer : Ans: b

Description : In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to (a) collect liquid refrigerant and prevent it from going to compressor (b) detect liquid in vapour (c) superheat the vapour (d) increase refrigeration effect

Last Answer : Ans: a

Description : Condensing temperature in a refrigerator is the temperature (a) of cooling medium (b) of freezing zone (c) of evaporator (d) at which refrigerant gas becomes liquid

Last Answer : Ans: d

Description : In refrigerator, liquid receiver is required between condenser and flow controlling device, if quantity of refrigerant for system is (a) less than 2 kg (b) more than or equal to 3.65 kg (c) more than 10 kg (d) there is no such consideration

Last Answer : Ans: b

Description : The bank of tubes at the back of domestic refrigerator are (a) condenser tubes (b) evaporator tubes (c) refrigerant cooling tubes (d) capillary tubes

Last Answer : Ans: a

Description : When, H1 = Total heat of air entering the coil (heating or cooling) H2 = Total heat of air leaving the coil (heating or cooling) H3 = Total heat of air at the end of ... A. cooling and humidification B. cooling and dehumidification C. heating and humidification D. heating and dehumidification

Last Answer : ANSWER : C

Description : What is sensible cooling of air? A. the cooling in which sensible heat of air is removed in order to reduce temperature B. the cooling in which temperature of air is reduced without changing in its moisture content C. both a. and b. D. none of the above

Last Answer : ANSWER : C

Description : In vapour compression cycle using NH3 as refrigerant, initial charge is filled at (a) suction of compressor (b) delivery of compressor (c) high pressure side close to receiver (d) low pressure side near receiver

Last Answer : Ans: c

Description : In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be (a) high, of the order of 25° (b) as low as possible (3 to 11°C) (c) zero (d) any value

Last Answer : Ans: b

Description : Alcohols alone cannot be used in CI engines as a) their self ignition temperature is high b) latent heat of vaporization is high c) all of the mentioned d) none of the mentioned

Last Answer : Answer: c Explanation: None.

Description : n a chemical factory where dyes are made, wet cake at 30 OC consisting of 60% moisture  is put in a dryer to obtain an output having only 5% moisture, at atmospheric pressure. In  each batch about 120 ... dryer and the dryer efficiency  is 80%. Latent heat of steam at 4 kg/cm2 is 520 kcal/kg.

Last Answer : Given that   Qty of material dried per batch - 120 Kgs  Moisture at inlet - 60% a. The quantity of moisture removed per batch.  Water quantity in a wet batch - 120 x 0.6 = 72 Kgs.  Quantity of bone dry ... - 48/0.95 = 50.5 Kgs.  Equivalent water in a dry batch - 50.5 - 48 = 2.5 Kgs.

Description : ick out the undesirable property for a good refrigerant. (A) High thermal conductivity (B) Low freezing point (C) Large latent heat of vaporisation (D) High viscosity

Last Answer : (D) High viscosity

Description : The coefficient of performance is the ratio of the refrigerant effect to the (a) heat of compression (b) work done by compressor (c) enthalpy increase in compressor (d) all of the above

Last Answer : Ans: d

Description : Choose the wrong statement (a) Temperature of medium being cooled must be below that of the evaporator (b) Refrigerant leaves the condenser as liquid (c) All solar thermally operated absorption systems are capable only of intermittent operation (d) frost on evaporator reduces heat transfer

Last Answer : Ans: a

Description : Humidification is the process of addition moisture in air at A. constant wet bulb temperature B. constant dry bulb temperature C. constant latent heat D. none of the above

Last Answer : ANSWER : B

Description : When air passes through silica gel, A. it absorbs water vapour molecules B. latent heat of condensation is released C.dbt of air increases D. all of the mentioned

Last Answer : ANSWER : D

Description : Describe any two sources of air leak in surface condenser. Also describe effect of air leak on latent heat of steam and cooling water requirements.

Last Answer : ✓ The main sources of air leakage found in condenser are given below: 1) There is leakage of air from atmosphere at the joint of the parts which are internally under a pressure less ... hence evaporation enthalpy of steam increases therefore more amount of cooling water required in the condenser. 

Description : An ideal liquid refrigerant should (A) Not have a sub-atmospheric vapour pressure at the temperature in the refrigerator coils (B) Not have unduly high vapour pressure at the condenser temperature (C) Both (A) and (B) (D) Have low specific heat

Last Answer : (C) Both (A) and (B)

Description : The condition of refrigerant before entering the expansion or throttle valve, in a vapour compression system (a) dry vapour (b) wet vapour (c)liquid-vapour mixture (d) high pressure saturated liquid

Last Answer : Ans: d

Description : For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphereis high, then (a) bigger cabinet should be used (b) smaller cabinet should ... tight vapour seal should be used (d) refrigerant with lower evaporation temperature should be used

Last Answer : Ans: c

Description : In vapour compression cycle, the condition of refrigerant is high pressure saturated liquid (a) after passing through the condenser (b) before passing through the condenser (c) after passing through the expansion or throttle valve (d) before entering the expansion valve

Last Answer : Ans: d

Description : In sensible cooling process the relative humidity: A. decreases B. increases C. remains constant D. none of the above

Last Answer : ANSWER : B

Description : The horizontal line in psychrometric chart joining the change of state of air represents A. humidification B. sensible cooling or heating C. sensible cooling or heating with humidification D. sensible cooling or heating with dehumidification

Last Answer : ANSWER : B

Description : In sensible heating or cooling, A. work done remains constant B. dry bulb temperature or air remains constant C. both of the mentioned D. none of the mentioned

Last Answer : ANSWER : A

Description : Why high latent heat of vaporisation is desirable in a refrigerant ?

Last Answer : A high latent heat of vaporisation of refrigerant results in small amount of refrigerant and thus lesser circulation system of refrigerant for same tonnage.

Description : High __________ is an undesirable property for a good refrigerant. (A) Specific heat (B) Latent heat of vaporisation (C) Viscosity (D) Specific vapor volume

Last Answer : (C) Viscosity

Description : Heat in BTU necessary to increase the temperature of 1 lb of gas and its accompanying vapour by 1°F is called the (A) Latent heat (B) Humid heat (C) Specific heat (D) Sensible heat

Last Answer : (C) Specific heat

Description : McCabe-Thiele method of binary distillation does not assume that the (A) Sensible heat changes are negligible compared with latent heat changes (B) Molar latent heats of all components are equal (C) Heat of mixing is negligible (D) None of these

Last Answer : (D) None of these

Description : Removal of __________ heat is involved in the condensation of a vapor under saturated conditions. (A) Super (B) Sensible (C) Latent (D) Both (B) & (C)

Last Answer : (B) Sensible

Description : What do the term sensible heat and latent heat mean?

Last Answer : Sensible heat: We can measure the rise in temperature. When we add more heat to a substance. Example - heat that added to water from 0º C to 100º C. This added heat is measured as sensible heat. ... at 100º C though we added more heat the temperature remains at 100º C till all water becomes steam.  

Description : An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a (A) Boiler (B) Heat exchanger (C) Recuperator (D) Regenerato

Last Answer : (B) Heat exchanger

Description : In a cooling tower, water becomes cool by (A) Loosing sensible heat (B) Heat transfer to surroundings (C) Vaporisation due to heat loss to air (D) Loosing latent heat

Last Answer : (A) Loosing sensible heat

Description : Net calorific value is the gross calorific value less the __________ heat of water in the product of combustion when cooled to 15°C. (A) Sensible (B) Latent (C) Sensible and latent (D) None of these

Last Answer : (C) Sensible and latent

Description : Evaporative cooling process employs a combination of cooling and humidification in which the (A) Sensible heat is added (B) Sensible heat is removed and the latent heat is added (C) Latent heat is removed (D) Sensible heat is added and latent heat is removed

Last Answer : Option B

Description : What refers to the heat needed to change the temperature of the substances without changing its phases?  a. Latent heat  b. Sensible heat  c. Specific heat  d. entropy

Last Answer : Sensible heat

Description : Heat that cause change in phase without a change in temperature.  a) Sensible Heat  b) Latent Heat  c) Thermo Heat  d) None of the above

Last Answer : Latent Heat

Description : Heat that cause change in temperature at without a change in phase.  a) Sensible Heat  b) Latent Heat  c) Thermo Heat  d) None of the above

Last Answer : Sensible Heat

Description : Which of the following cannot be measured by a thermometer?  a. Latent Heat  b. Sensible Heat  c. Specific Heat  d. Heat of Fusion

Last Answer : Latent Heat

Description : Heat which causes a change in temperature of a substance.  a. Latent heat  b. Sensible heat  c. Specific heat  d. Heat of Fusion

Last Answer : Sensible heat

Description : The quantity of heat required to raise the temperature of a given substance by 1 oC is known as: a) sensible heat b) specific heat c) heat capacity d) latent heat

Last Answer : specific heat specific heat is the quantity of heat required to raise the temperature of 1 gram substance by 1 oC is

Description : Define sensible heat and latent heat 

Last Answer : Latent heat: It is defined as the quantity of heat required for phase change of working substance at saturation temperature. OR The amount of heat added at saturation temperature is called latent ... thermometer. OR The amount of heat added up to saturation temperature is called sensible heat.

Description : Define: (i) Sensible heat (ii) Latent heat

Last Answer : i) Sensible Heat: The heat in which change in temperature of a substance can be observed but phase remains unchanged that heat is known as Sensible heat.  This heat can be sensed by ordinary ... of fusion Heat at which Liquid Changes Phase to vapour is known as Latent heat of vaporization

Description : The formation of frost on cooling coils in a refrigerator (a) increases heat transfer (b) improves C.O.P. of the system (c) increases power consumption (d) reduces power consumption

Last Answer : Ans: c

Description : Formation of frost on evaporator in refrigerator (a) results in loss of heat due to poor heat transfer (b) increases heat transfer rate (c) decreases compressor power. (d) can be avoided by proper design

Last Answer : Ans: a

Description : Identify modes of heat transfer involved applications with brief explanation. (1) Radiator of automobile (2) Condenser of domestic refrigerator.

Last Answer : Modes of heat transfer Automobile radiator-A radiator is a type of heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through ... of heat transfer plays very important deciding factor transferring heat from condenser tube to atmosphere.  

Description : In milk chilling plant, the usual secondary refrigerant is (a)ammonia (b)sodium silicate (c) glycol (d) brine

Last Answer : Ans: d

Description : The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperatureconstant, will (a) increase (b) decrease (c) may increase or decrease depending on the type of refrigerant used (d) remain unaffected

Last Answer : Ans: a

Description : The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will (a) increase (b) decrease (c) remain unaffected (d) may increase or decrease depending on the type of refrigerant used

Last Answer : Ans: a