Heat Pump Efficiency: Temperature's Role in Refrigeration, AC, WWTP

This report investigates the impact of temperature on the efficiency of heat pumps in refrigeration, air conditioning, and waste water treatment plants. It reviews literature on the subject, focusing on factors like compression ratio, condensation temperature, and refrigerant flow. The report explains the coefficient of performance (COP) for refrigerators and heat pumps, highlighting how it measures efficiency. Furthermore, it explores the applications of heat pumps in HVAC systems and waste water treatment plants, discussing how they transfer heat and improve energy efficiency. Quantitative research methods are used to analyze the data, emphasizing the use of numerical comparisons and statistical inferences. The report concludes by referencing relevant sources and online resources to support the findings and analysis. This report aims to provide a comprehensive understanding of the role of temperature in heat pump performance across various applications.

How does the temperature affect
the efficiency of a heat pump in a
refrigerator, air conditioner and
waste water treatment plant?

Table of Contents
PROBLEM DEFINITION...............................................................................................................3
LITERATURE RIVIEW.................................................................................................................3
Quantitative and qualitative methods..........................................................................................4
REFERENCE...................................................................................................................................6

PROBLEM DEFINITION
How does the temperature affect the efficiency of a heat pump in a refrigerator, air
conditioner and waste water treatment plant?
LITERATURE RIVIEW
According to Jinshun Wu, Chao Chen (2019), The compressor, evaporators and cooling
fans are installed outside the packed area. Where as, the fluorine water plates heat exchange, air
conditioner, pumps, etc. are stored in the internal area of the premises or homes ( ADAVANCES
IN MECHANICAL ENGINEERING, 2019). Therefore various factors which influences the
performance and efficiency of the heat pumps air conditioning system that includes the
compression ratio, condensation temperature, refrigerant flow. Refrigerator has a heat pump
which helps in maintaining the coolness or temperature of the body lower than the atmospheric
temperature. This is done with the help of pulling out the heat from the cold physical structure
and delivering it to the hot structure. The performance of the refrigerator is measured by
considering the ratio of amount of heat which has been extracted from the cold structure to the
amount of work which is to be done on the systems (Sharafian and Bahrami, 2014). This ratio is
referred to as coefficient of performance of refrigerator. In mathematical form, it is expressed in
the following manner which helps in improving efficiency of the refrigerator:
Wr = Q2 - Q1
In the above formulae, Wr stands for the work which is required to be done, Q2 is the hot
temperature of the refrigerators heat pump and Q1 is the cold temperature.
Furthermore, the refrigerator uses heat pump which is useful for cooling in summer and
can be used for heating during the winter season. So the performance of heat pump in
refrigerator is expressed by considering the ratio of amount of heat delivered to the quantity of
work which is required to be accomplished on the system (Brückner and et. al., 2015). This ratio
is referred to as coefficient of performance ratio of heat pump.
One of the best benefit of a heat pump over the standard heating ventilating and air
conditioning (HVAC) unit is that there is no requirement of installing different systems to heat
and cool the homes and other commercial premises (How Heat Pumps Work, 2019). Heat pumps
works efficiently to transfer heat rapidly and their proper installation and functioning helps in
maintaining the atmosphere cool by minimising the humidity levels. Heat pump helps in pulling

the warm air from the house and other premises with the help of motorised fan and a compressor
which is installed outside room helps in circulating refrigerant between the inside evaporator and
outside condensing units. This device uses a very little amount of energy fro transferring heat
from one location to another. There are various types of heat pumps and all operates on the same
basis. Than the warm air which is there inside the room or house or any other premises is
transferred to the outside with the help of air handler while refrigerant is pumped from the
external condenser coil to the internal evaporator coil. Furthermore, the refrigerant absorbs the
heat when it passes over the inside air. This finally helps in minimising the room temperature
and cool air is pushed inside the room with the help of connecting inside ducts to air vents.
According to Leonid N. Alekseiko, Viacheslav V. Slesarenko (2019), Waste water
treatment plan produces a large quantity of waste heat energy. These plants emphasises on the
energy efficiency of the projects. Heat pumps increases efficiency of waste water treatment
plants by using large amount of thermal and electrical energies (Combination of waste water
treatment plants and heat pumps, 2019). When the water has been treated effectively and
efficiently then it is to be discharged as affluent typically into a local body of water. The ground
source heat pumps helps in directly transferring the heat from the ground by absorbing it with the
help of buried pipes which are filled with water and they are better dehumidifiers. It operates at
50- 60 degree Fahrenheit and the water is available throughout the year because it stops the
operations. The heat of urban sewage can be used as the heat source for the purpose of hot water
and heating. Waste water treatment plant after pumped through heat exchangers heat pumps.
After use by the HP system, the waste transfers through the passage and flows into the sea or
river. The evacuation after the HP will not change. The temperature of waste water is minimised
by 7- 10 degree Celsius. In the community area, an abstracted heat exchanger is used to heat and
cold water at 60 -70 degree Celsius (Herold, Radermacher and Klein, 2016). The heated water is
then pumped into the thermal network of the city. During the summer season, the HP generates
40 – 50 percent of the heat for the intention of heating the hot water which is to be transferred to
the urban population.
Quantitative and qualitative methods
Quantitative research is those research which uses quantifiable data or information which
helps in investigating the social phenomenon and assumes a fixed and measurable reality

(Gadhamshetty, Gude and Nirmalakhandan, 2014). In this data are analysed and interpreted with
the help of numerical comparisons and statistical inferences.
Qualitative research methods are those which use collection of those information that are
concerned with describing a subject rather than measuring and evaluating it. In this data are
collected through observation and focus groups.
Therefore in this research, quantitative research has been used by the researcher to
analyse the impact of temperature on the efficiency of the heat pump in the refrigerator, air
conditioner and waste water treatment plant. This method will provide effective and efficient
results because it uses objectives and numerical data which enhances on accuracy and
objectivity. In this a problem or issue is measured by deductively forming the hypothesis. Each
step used in this method is standardised to minimise bias while collecting data and analysing
information (Hepbasli and et. al., 2014). Furthermore, it is easy to calculate the data in numerical
terms as coefficient of performance ratio was used.

REFERENCE
Brückner and et. al., 2015. Industrial waste heat recovery technologies: an economic analysis of
heat transformation technologies. Applied Energy.151. pp.157-167.
Gadhamshetty, V., Gude, V.G. and Nirmalakhandan, N., 2014. Thermal energy storage system
for energy conservation and water desalination in power plants. Energy.66. pp.938-949.
Hepbasli and et. al., 2014. A key review of wastewater source heat pump (WWSHP) systems.
Energy Conversion and Management.88. pp.700-722.
Herold, K.E., Radermacher, R. and Klein, S.A., 2016. Absorption chillers and heat pumps. CRC
press.
Sharafian, A. and Bahrami, M., 2014. Assessment of adsorber bed designs in waste-heat driven
adsorption cooling systems for vehicle air conditioning and refrigeration. Renewable
and Sustainable Energy Reviews.30. pp.440-451.
Online
How Heat Pumps Work. 2019. [Online]. Available Through :
<https://home.howstuffworks.com/home-improvement/heating-and-cooling/heat-pump.htm>.
Combination of waste water treatment plants and heat pumps. 2019. [Online]. Available
Through :
<https://www.researchgate.net/publication/273489868_Combination_of_wastewater_treatment_
plants_and_heat_pumps>.
ADAVANCES IN MECHANICAL ENGINEERING. 2019. [Online]. Available Through :
<https://journals.sagepub.com/doi/full/10.1155/2013/843013>.