What is Carnot refrigerator: Definition and 18 Discussions
Thermodynamic heat pump cycles or refrigeration cycles are the conceptual and mathematical models for heat pump, air conditioning and refrigeration systems. A heat pump is a mechanical system that allows for the transmission of heat from one location (the "source") at a lower temperature to another location (the "sink" or "heat sink") at a higher temperature. Thus a heat pump may be thought of as a "heater" if the objective is to warm the heat sink (as when warming the inside of a home on a cold day), or a "refrigerator" or “cooler” if the objective is to cool the heat source (as in the normal operation of a freezer). In either case, the operating principles are close. Heat is moved from a cold place to a warm place.
I think I calculated part a correctly by extracting the cp (specific heat) of water from the table which is 4.188
Then calculated Q_dot by simply using the equation Q=m*c*deltaT=10.47kW
But I am stuck at part b, I know that the heat extracted from the water is the same as Q_L (rate of heat...
If a Carnot refrigerator requires a work input of only 230 J to extract 346 J of heat from the cold reservoir.
Doesn’t this discrepancy imply a violation of the law of conservation
of energy?
Homework Statement
In an ideal refrigeration cycle, the temperature of the condensing vapour is 40oC and the temperature during evaporation is -20oC. Determine the coefficient of performance of this cycle for the working fluids; R12 and ammonia.
Homework Equations
C.O.Pc = TL/(TH-TL)
The...
Homework Statement
Cooling of a food from 293K (20 ⁰C), freezing it at 272K (-1⁰C), and further cooling to 253K (-20 ⁰C); using cooling water rising in temperature from 293K (20 ⁰C) to 303K (30 ⁰C) to accept heat. The specific heat of the unfrozen food is taken as 3.2 kJ/kg K, that of the...
Homework Statement
The temperature inside the room ##T_I= 25 C ## and the temperature outside the house is ##T_O = 32C##. The temperature difference causes energy to flow into the room (by conduction through the walls and window glass) at the rate 3,000 J/s. To return this energy to the...
Considering two thermal energy reservoirs, one at a higher temperature of TH compared to the other at TL, if we operate a reversible refrigeration cycle between the reservoirs then its coefficient of performance is given by,
COPR,rev=TL/TH-TL
This is the basically the maximum COP a...
Homework Statement
An ideal refrigerator utilizes a carnot cycle operating between 0 and 25 degrees celsius. To turn 10 kg of water at 0 degrees celsius into 10 kg of ice at 0 degrees celsius,
a) how much heat is exhausted into the room?
b) how much energy must be supplied to the...
Carnot engine efficiency is:
\eta_{work} = 1 - \frac{T_c}{T_h}
Carnot refrigeration efficiency is:
\eta_{cool} = \frac{ T_c }{T_h-T_c}
\eta_{cool} = \frac{ 1 }{\frac{T_h}{T_c} - 1}
Simple multiplication should give me the efficiency where both the engine and the refrigeration share the...
As per II law of thermodynamics you it is NOT possible that a hotter body becomes hotter and colder body becomes colder when in contact. But in a Carnot refrigerator, the heat is taken from a cold reservoir and pushed to a hotter one. It sort of opposite the II law. Help me over this paradoxical...
Homework Statement
433J of heat is extracted from a massive object at 0\circC while rejecting heat to a hot reservoir at 19\circC.
What minimum amount of work will accomplish this? Answer in units of J.
Homework Equations
COP= Qc/(Qh-Qc) = Tc/(Th-Tc)
The Attempt at a Solution...
Homework Statement
Three kilograms of liquid water at 0° C is put into the freezer compartment of a Carnot refrigerator. The temperature of the compartment is -13.5° C, and the temperature of the kitchen is 24.5° C. If the cost of electrical energy is ten cents per kilowatt · hour, how much...
Hi All,
My textbook mentions that the coefficient of refrigeration for a Carnot refrigerator acting between a hot reservoir T_{H} and a cold reservoir T_{C} is
K_{Carnot} = \frac{T_C}{T_H - T_C}
This got me wondering - Suppose you had 1 kg of ice at it's melting point, and 1 kg of water...
Homework Statement
can you please help me solve this problem?
A carnot refrigerator takes heat from water @ 0 degrees celsius and rejects heat to a room at 27 degrees celsius. If 50 kg of water @ 0 degrees celsius is converted to ice @ 0 degrees celsius, how much energy must be supplied...
Homework Statement
A Carnot refrigerator operating between -30.0 ^ C and + 20.0 ^ C extracts heat from the cold reservoir at the rate 300 J/s. What are (a) the coefficient of performance of this refrigerator, (b) the rate at which work is done on the refrigerator and (c) the rate at which heat...
Homework Statement
a carnot refrigerator takes heat from water at 0 degree celsius and rejects heat to a room at 27 degree celsius. if 50kg of water at 0 degree celsius is converted to ice at 0 degree celsius. how much energy must be supplied to the refrigerator? Homework Equations
Sorry, i...
A Carnot refrigerator operating between -10.0 C and 40.0 C extracts heat from the cold reservoir at the rate 300 J/s. What are (a) the coefficient of performance of this refrigerator, (b) the rate at which work is done on the refrigerator and (c) the rate at which heat is exhausted to the hot...
The question reads...
A heat pump is essentially a refrigerator engine that uses the inside of a building as a hot reservoir in the winter and the outside of the building as the hot reservoir in the summer. A) For a carnot refrigerator engine operating between 25 C and 40 C in the summer, what...
This is just a common problem solving question, which I cannot make, I suspect because I'm bad at maths. Anyway, I want to see it done, hopefully to grasp it. I am doing physics, so, it's an exercise from one of my books.
18-11. Show that the efficiency e of a Carnot engine and the...