Coefficient of Performance of Heat Pump
LaGuardia Community College Thermodynamics
Lab Report
Coefficient of Performance of Heat Pump June 9, 2015
Authors: Kamal Ouanaim Instructor: Dr. Yves Ngabonziza
Abstract
This experiment was conducted to determine the Coefficient of Performance of a heat pump working in both modes: heating and cooling a closed system. The circuit used in the experiment was specifically designed to measure four data points via sensors. The collected data is actively logged into PASCOCapstone software to determine the amount the Temperature, Heat, Power and calculate the Coefficient of Performance of the Heat Pump used in the experiment.
Introduction
A heat pump is a very sophisticated apparatus because of its ability to pump heat from or into a closed system from the surrounding environment. An example of a heat pump is a refrigerator or an air conditioner and can be considered the most used tools in our days. The principle of the heat pump is to take in work and pump out the undesired heat. Thus, it is natural to ask: what the ratio of the desired heat is out verses the work in? The answer to this question is given by the Coefficient of Performance of heat pump and its formula is
=
[1]. The
conducted experiment’s objective is to calculate a coefficient of performance of a model of a heat pump using a specific circuit with two aluminum plates one used as closed system and the other as surrounding environment. Thus, the desired heat at the aluminum plate is given by Q = mc∆T [1], where m is the mass of the aluminum plate and c is the specific heat of the aluminum which equals to 0.90 J/(g.oC) [1] and ∆T is the change in temperature. The input work is defined by the area under the curve Power vs time. The power is this case is defined by
Voltage multiplied by the Current:
=
× [1]. All these data point are collected via sensors
and instantly logged into PASCOCapstone software to perform the analysis.
Results
Figure 1: PASCOCapstone measurement for the Heat Pump used as Refrigerator
The refrigerator coefficient of performance in this case is: =
=
63.51 = 1.84 34.48
Figure 2: PASCOCapstone measurement for the Heat Pump used as Heat Engine
The coefficient of performance in this case is: =
=
95.67 = 2.34 40.89
Discussion
The results of the experiment are very successful, because the coefficient of performance is greater than 1. Thus the ratio Heat produced verses Work consumed is not one to one
relationship, which makes this experiment successful. The result of the first part of the experiment KR = 1.84 units meaning the heat produced is almost double of the power consumed. The result on the second part are even greater, where KH = 2.34 units which is more than double of the power consumed.
Conclusion The experiment allowed me to learn how to apply and use software toolboxes for my experimental procedure to analyze the problem in question which is determining the coefficient of performance of a heat pump model. I’ve also learned how to approach a problem from different angles, use different methods to build an advanced understanding and conclude with a solution that can be further analyzed and applied for future problems. The strengths of this study is to demonstrate the importance of software applications to real word engineering problems and research and how close it can come to physical experiments.
References [1] PASCO, Model No. ET-8792: Experiment 4: Coefficient of Performance.
Lab Report
Coefficient of Performance of Heat Pump June 9, 2015
Authors: Kamal Ouanaim Instructor: Dr. Yves Ngabonziza
Abstract
This experiment was conducted to determine the Coefficient of Performance of a heat pump working in both modes: heating and cooling a closed system. The circuit used in the experiment was specifically designed to measure four data points via sensors. The collected data is actively logged into PASCOCapstone software to determine the amount the Temperature, Heat, Power and calculate the Coefficient of Performance of the Heat Pump used in the experiment.
Introduction
A heat pump is a very sophisticated apparatus because of its ability to pump heat from or into a closed system from the surrounding environment. An example of a heat pump is a refrigerator or an air conditioner and can be considered the most used tools in our days. The principle of the heat pump is to take in work and pump out the undesired heat. Thus, it is natural to ask: what the ratio of the desired heat is out verses the work in? The answer to this question is given by the Coefficient of Performance of heat pump and its formula is
=
[1]. The
conducted experiment’s objective is to calculate a coefficient of performance of a model of a heat pump using a specific circuit with two aluminum plates one used as closed system and the other as surrounding environment. Thus, the desired heat at the aluminum plate is given by Q = mc∆T [1], where m is the mass of the aluminum plate and c is the specific heat of the aluminum which equals to 0.90 J/(g.oC) [1] and ∆T is the change in temperature. The input work is defined by the area under the curve Power vs time. The power is this case is defined by
Voltage multiplied by the Current:
=
× [1]. All these data point are collected via sensors
and instantly logged into PASCOCapstone software to perform the analysis.
Results
Figure 1: PASCOCapstone measurement for the Heat Pump used as Refrigerator
The refrigerator coefficient of performance in this case is: =
=
63.51 = 1.84 34.48
Figure 2: PASCOCapstone measurement for the Heat Pump used as Heat Engine
The coefficient of performance in this case is: =
=
95.67 = 2.34 40.89
Discussion
The results of the experiment are very successful, because the coefficient of performance is greater than 1. Thus the ratio Heat produced verses Work consumed is not one to one
relationship, which makes this experiment successful. The result of the first part of the experiment KR = 1.84 units meaning the heat produced is almost double of the power consumed. The result on the second part are even greater, where KH = 2.34 units which is more than double of the power consumed.
Conclusion The experiment allowed me to learn how to apply and use software toolboxes for my experimental procedure to analyze the problem in question which is determining the coefficient of performance of a heat pump model. I’ve also learned how to approach a problem from different angles, use different methods to build an advanced understanding and conclude with a solution that can be further analyzed and applied for future problems. The strengths of this study is to demonstrate the importance of software applications to real word engineering problems and research and how close it can come to physical experiments.
References [1] PASCO, Model No. ET-8792: Experiment 4: Coefficient of Performance.
