scholarly journals Linear Regression Analysis and Techno-Economic Viability of an Air Source Heat Pump Water Heater in a Residence at a University Campus

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2280
Author(s):  
Christy E. Manyi-Loh ◽  
Mandlenkosi Sikhonza ◽  
Stephen Tangwe
Keyword(s):  
Linear Regression ◽  
Heat Pump ◽  
Net Present Value ◽  
Linear Regression Analysis ◽  
Electrical Energy ◽  
Hot Water ◽  
Load Factor ◽  
Water Heater ◽  
Air Source Heat Pump ◽  
Electric Boiler

This study quantifies the potential of a 4.0 kW air source heat pump (ASHP) unit retrofitted to a 12.0 kW, 1000 L electric boiler coupled to a 1000 L storage tank. A data acquisition system was built to monitor the performance of the electric boiler and the ASHP water heater. The annual electrical energy saving and the load factor reduction from the electric boiler because of the ASHP unit retrofit was 34,805.94 kWh and 0.124. The net present value payback period of the ASHP system was 1.60 years. A Wilcoxon rank sum test was employed to compare both the volumes of hot water and electrical energy consumed by the two systems. Linear regression models of the daily volumes of hot water and electrical energy consumed by both systems were established. The results should be of great value to the management of universities that are considering energy-efficient interventions with a significant return on investment.

The Solar Energy-Air Source Heat Pump Was Applied to the Hot Water System

2014 ◽  
Vol 587-589 ◽  
pp. 243-246
Author(s):  
Chu Ping Lu ◽  
Kai Ji
Keyword(s):  
Solar Energy ◽  
Heat Pump ◽  
Water System ◽  
Hot Water ◽  
Water Heater ◽  
Circulating Water ◽  
Air Source Heat Pump ◽  
Hot Water Supply ◽  
The City

This paper is as an example of the hot water supply of the hotel in the city,The design of the hot water system is the solar energy and the air source heat pump,includes:the selection calculation of the air source heat pump of the water heater , the selection and calculation of the solar collector,the determination of the thermal storage tank and the determination of the circulating water pump of heat collecting .

Analysis of Domestic Hot Water Production Efficiency for Detached Houses

2015 ◽  
Vol 797 ◽  
pp. 185-191
Author(s):  
Arkadiusz Gużda ◽  
Norbert Szmolke
Keyword(s):  
Heat Pump ◽  
Production Efficiency ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Production ◽  
Water Heater ◽  
Domestic Hot Water ◽  
Air Source Heat Pump ◽  
Heat Pump Water Heater ◽  
Detached House

The article compares two means for domestic hot water production (DHW) for a detached house that is using gas boiler with a closed combustion chamber and air source heat pump water heater (ASHPWH). An analysis of domestic hot water production using an air source heat pump was made taking into account coefficient of performance listed according to the new BS EN 16147 standard. The analysis of outlay related to the investment and operating costs was also performed. Ultimately, the more profitable choice for domestic hot water production was made.

The Experimental Study of Thermodynamic Performance on R407C Air-Conditioner Hot Water Combined Unit

2011 ◽  
Vol 467-469 ◽  
pp. 549-553
Author(s):  
Hong Song Hu ◽  
Fang Wang ◽  
Jian Zhong Yu ◽  
Wu Hao
Keyword(s):  
Heat Pump ◽  
Paper Analysis ◽  
Hot Water ◽  
Air Conditioner ◽  
Water Heater ◽  
Operation Conditions ◽  
Air Source Heat Pump ◽  
Heat Pump Water Heater ◽  
Environmental Friendly ◽  
Thermodynamic Performance

This paper analysis on the design and the test of an air-conditioner hot water combined unit using environmental friendly refrigerant R407C. Firstly the research status of the system is elaborated for air-source heat pump water heater simply. Then the principle and structure are described on an air-conditioner heat pump followed by a water heater at different running modes and different operation conditions. The hot water experiments of the unit in three seasons have been tested and researched in a multi-functional environmental chamber. Some analysis of the unit’s thermodynamic performance is carried out from the test data for improving such kind of machine afterward.

Prediction of coefficient of performance and simulation design of an air-source heat pump water heater

2017 ◽  
Vol 15 (03) ◽  
pp. 378-394 ◽  
Author(s):  
Stephen Loh Tangwe ◽  
Michael Simon ◽  
Edson Leroy Meyer
Keyword(s):  
Electrical Energy ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Ambient Conditions ◽  
Water Heater ◽  
Content Type ◽  
Air Source Heat Pump ◽  
Significant Difference ◽  
Air Speed ◽  
Heating Up

Purpose The purpose of this study was to build and develop mathematical models correlating ambient conditions and electrical energy to the coefficient of performance (COP) of an air-source heat pump (ASHP) water heater. This study also aimed to design a simulation application to compute the COP under different heating up scenarios, and to calculate the mean significant difference under the specified scenarios by using a statistical method. Design/methodology/approach A data acquisition system was designed with respect to the required sensors and data loggers on the basis of the experimental setup. The two critical scenarios (with hot water draws and without hot water draws) during the heating up cycles were analyzed. Both mathematical models and the simulation application were developed using the analyzed data. Findings The predictors showed a direct linear relationship to the COP under the no successive hot water draws scenario, while they exhibited a linear relationship with a negative gradient to the COP under the simultaneous draws scenario. Both scenarios showed the ambient conditions to be the primary factor, and the weight of importance of the contribution to the COP was five times more in the scenario of simultaneous hot water draws than in the other scenario. The average COP of the ASHP water heater was better during a heating cycle with simultaneous hot water draws but demonstrated no mean significant difference from the other scenario. Research limitations/implications There was a need to include other prediction parameters such as air speed, difference in condenser temperature and difference in compressor temperature, which could help improve model accuracy. However, these were excluded because of insufficient funding for the purchase of additional temperature sensors and an air speed transducer. Practical implications The research was conducted in a normal middle-income family home, and all the results were obtained from the collected data from the data acquisition system. Moreover, the experiment was very feasible because the conduction of the study did not interfere with the activities of the house, as occupants were able to carry out their activities as usual. Social implications This paper attempts to justify the system efficiency under different heating up scenarios. Based on the mathematical model, the performance of the system could be determined all year round and the payback period could be easily evaluated. Finally, from the study, homeowners could see the value of the efficiency of the technology, as they could easily compute its performance on the basis of the ambient conditions at their location. Originality/value This is the first research on the mathematical modeling of the COP of an ASHP water heater using ambient conditions and electrical energy as the predictors and by using surface fitting multi-linear regression. Further, the novelty is the design of the simulation application for a Simulink environment to compute the performance from real-time data.

Performance optimization of an air source heat pump water heater using mathematical modelling

2015 ◽  
Vol 26 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Stephen Tangwe ◽  
Michael Simon ◽  
Edson L. Meyer ◽  
Sampson Mwampheli ◽  
Golden Makaka
Keyword(s):  
Ambient Temperature ◽  
Heat Pump ◽  
Performance Optimization ◽  
Rate Of Change ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Tank ◽  
Water Heater ◽  
Conservation Of Energy ◽  
Air Source Heat Pump

In South Africa, there is an ongoing constraint on the electricity supply at the national grid to meet the demand. Eskom is implementing various measures such as the Integrated Demand Management and the promotion and encouragement of the use of energy efficient devices like an Air Source Heat pump (ASHP) water heater to replace the high electrical energy consuming conventional geysers for sanitary hot water production. The ASHP water heater market is fast gaining maturity. A critical mathematical model can lead to performance optimization of the systems that will further result in the conservation of energy and significant reduction in global warming potential. The ASHP water heater comprises of an ASHP unit and a hot water storage tank. In this study, a data acquisition system (DAS) was designed and built which monitored the energy used by the geyser and the whole building, the temperature at the evaporator, condenser, tank outlet hot water, tank inlet cold water, the ambient temperature and relative humidity in the vicinity of the ASHP evaporator. It is also worthy to mention that the DAS also included to a flow meter and two additional temperature sensors that measured the volume of water heated and inlet and outlet water temperature of the ASHP. This work focused on using the mathematical equation for the Coefficient of Performance (COP) of an ideal Carnot’s heat pump (CHP) water heater to develop basic computation in M-file of MATLAB software in order to model the system based on two reservoir temperatures: evaporator temperatures (Tevp) of 0°C to 40°C (approximated to ambient temperature, Ta) and condenser temperatures (TCon) set at 50°C, 55°C and 60°C (approximated to the hot water set temperature of 50°C, 55°C and 60°C) respectively. Finally, an analytical comparison of a CHP water heater to the practical ASHP water heater was conducted on a hot water set point temperature of 55°C. From the modelling results, it can be deduced that at 0°C Tevp, the COP was 5.96 and 2.63 for CHP and ASHP water heater respectively, at a hot water set temperature of 55°C. Above 20°C Tevp, the rate of change of COP increased exponentially for the ideal CHP system, but was constant at 0.01/°C for the practically modelled ASHP water heater.

scholarly journals Performance assessment between a ground coupled and air source heat pump used for domestic hot water preparation

2019 ◽  
Vol 111 ◽  
pp. 06075
Author(s):  
Calin Sebarchievici
Keyword(s):  
Heat Pump ◽  
Simulation Models ◽  
Electrical Energy ◽  
Heat Pumps ◽  
Hot Water ◽  
Pump System ◽  
Heat Pump System ◽  
Domestic Hot Water ◽  
Air Source Heat Pump ◽  
Systems Simulation

A ground-coupled heat pump system (GCHP) and an air source heat pump (ASHP) driven by photovoltaic panels are used to provide domestic hot preparation for a NZEB house. The experimental measurements are used to test both the heat pump models in the same conditions of water temperature and volume of domestic hot water. A comparative analysis of the two heat pumps for domestic hot water preparation is performed. In addition, using the software TRNSYS (Transient Systems Simulation), two numerical simulation models of thermal and electrical energy consumption in DHW mode are developed. Finally, the simulations obtained using TRNSYS software are analysed and compared to the experimental data.

The Performance Analysis on the 75°C Hot Water of the Air Source Heat Pump Using R134A

2012 ◽  
Vol 482-484 ◽  
pp. 758-762
Author(s):  
Xing Wang Zhu ◽  
Chun Xia Hu ◽  
Yan Li Lv ◽  
Chao Xin Wang ◽  
Yu Gui Su
Keyword(s):  
Heat Pump ◽  
Input Power ◽  
Hot Water ◽  
Water Tank ◽  
Water Heater ◽  
Exhaust Temperature ◽  
Air Source Heat Pump ◽  
Heat Pump Water Heater ◽  
Good Energy ◽  
Saving Effect

In this paper the system of air-source heat pump water heater(ASHPWH) using R134A to get 75°C hot water is proposed. The experiments on the performance of ASHPWH are conducted in two typical conditions, one for 7°C dry bulb temperature and 6°C wet bulb temperature, the other for 20°C dry bulb temperature and 15°C wet bulb temperature. In addition the variations of the suction temperature, the exhaust temperature, the suction pressure, the exhaust pressure, the transient heat capacity, the input power and COPs with the changing of the hot water tank temperature are analyzed. The results show that 75°C hot water can be produced steadily and the COPs are 2.84 and 3.68 respectively in two different conditions, therefore the ASHPWH has good energy saving effect.

The Logical Choice of Auxiliary Heat Source for Solar Energy Water Heating System

2012 ◽  
Vol 512-515 ◽  
pp. 303-306
Author(s):  
Xue Lai Liu ◽  
Guan Zhu Wang ◽  
Yong An Li ◽  
Xiao Feng Zhang
Keyword(s):  
Heat Pump ◽  
Operating Cost ◽  
Water System ◽  
Hot Water ◽  
Low Carbon ◽  
Water Heater ◽  
Low Carbon Economy ◽  
Water Heaters ◽  
Air Source Heat Pump ◽  
Heat Pump Water Heater

This article describes the solar hot water system, and establishes the computational model of hot water system. It analyzes the economical efficiency of solar water heaters which equipped with electric water heaters, gas water heaters and air-source heat pump water heaters. The results show that the initial investment of the system which equipped with an electric water heater and a gas water heater is almost, but the operating cost which equipped with a gas water heater system is lower. The operating cost which equipped with an air-source heat pump water heater is the lowest, though the initial investment is the highest. The solar hot water system which equipped with an air-source heat pump water heater has important reference value for going low-carbon economy road in China.

scholarly journals Evaluation of the coefficient of performance of an air source heat pump unit and an air to water heat pump

2021 ◽  
Vol 32 (1) ◽  
pp. 27-40
Author(s):  
S. Tangwe ◽  
K. Kusakana
Keyword(s):  
Heat Pump ◽  
Thermal Energy ◽  
Pressure Sensors ◽  
Electrical Energy ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Heaters ◽  
Air Source Heat Pump ◽  
Heat Pump Unit ◽  
The Difference

Air source heat pump (ASHP) water heaters are efficient devices for sanitary hot water heating. The coefficient of performance (COP) of the air to water heat pump (AWHP) is constantly lower than that of the corresponding ASHP unit. The study focused on determining the COP of both the ASHP unit and the AWHP. This was achieved by the implementation of both experimental and simulation methods, with the help of a data acquisition system and the REFPROP software. The system comprised of a 1.2 kW split type ASHP unit and a 150 L high pressure geyser. A power meter, flow meters, temperature sensors, pressure sensors, ambient temperature and relative humidity sensor were installed at precise locations on the split type AWHP. Controlled volumes of 150, 50 and 100 L were drawn off from the AWHP during the morning, afternoon and evening for a year. The average COP for the summer and winter, in terms of the input electrical and output thermal energies of the AWHP were 3.02 and 2.30. The COPs of the ASHP unit, in terms of the change in the enthalpies of the refrigerant at the inlet and the outlet of the condenser and the evaporator, were 3.52 and 2.65 respectively. The study showed that the difference between the COP of the ASHP unit and that of the AWHP could be ascribed to the electrical energy consumed by the fan and the water circulation pump during the vapour compression refrigeration cycles. The work provides an energy optimisation opportunity to the manufacturers of this technology, helping to enhance the efficiency and COP of ASHP water heaters. Highlights The COPt of the ASHP unit was higher than the COPe of the AWHP. The COPe of the AWHP was the ratio of the input electrical energy consumed and the output thermal energy gained by the stored water. The COPt of the ASHP unit was enthalpies-dependent and a function of inlet and outlet enthalpies of the evaporator and condenser. The inlet and outlet refrigerant temperatures profiles of the condenser confirmed thermal energy dissipation.

Analysis on the Operating Characteristics of Solar Water Heater in Combination with Air Source Heat Pump Water Heater

2011 ◽  
Vol 393-395 ◽  
pp. 601-603
Author(s):  
Ai Guo Jiang ◽  
Xiao Zhong Wang
Keyword(s):  
Water Temperature ◽  
Heat Pump ◽  
Hot Water ◽  
Solar Water Heater ◽  
Operating Characteristics ◽  
Water Heater ◽  
Solar Water ◽  
Air Source Heat Pump ◽  
Heat Pump Water Heater ◽  
Collector Efficiency

Solar water heater cannot supply hot water in cloudy and raining days alone. It in combination with air source heat pump water heater (ASHPWH) is a good choice. The performance of the two kinds of water heater is affected by the water temperature. It is important that the ASHPWH operate at a right temperature of the water. A solar water heater with 4m2 flat-plate collector assisted by a 1.5kW ASHPWH is studied in this paper. The results show that both the collector efficiency of the solar water heater and the COP of the ASHPWH system decreases as the water temperature increases. The highest and lowest collector efficiency of the solar water heater are 54.4% and 45.6% respectively. The COP of the ASHPWH system ranges from 6.48 to 2.61 as the water temperature increases. Operating sequences of these two kinds of water heater affect solar energy utilization ratio and the power input of the ASHPWH system.

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