scholarly journals The Viability of Capacity Control of High Temperature Heat Pump Water Heaters Operating Non-Azeotropic Mixtures

1997 ◽  
Author(s):  
Leon Liebenberg ◽  
Josua P. Meyer
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
Life Cycle Cost ◽  
Coefficient Of Performance ◽  
Capacity Control ◽  
Water Heater ◽  
Pump Operation ◽  
Water Heaters ◽  
Heat Pump Water Heater ◽  
Controlled Systems

A high temperature electrically-operated heat pump water heater is evaluated in terms of the viability of employing capacity control using non-azeotropic refrigerant mixtures (NARMs). The system coefficient of performance (COP) is improved by introducing capacity control, which offers continuous modulation by varying heat pump capacity to match the load. This is accomplished by using a non-azeotropic refrigerant mixture (NARM) and changing the composition (x) of the circulating mixture. The NARM R-22/ R-142b is selected due to the requirement for a high condensing temperature and a wide capacity range. The life-cycle cost effectiveness of this heat pump is compared with that of a conventional heat pump (operating a pure fluid). Computer simulations show that the capacity-controlled heat pump, operating between compositions of 100% R-22 and 70% R-22, shows a 29.6% improvement in energy conversion when compared with a conventional R-22 heat pump water heater. The payback periods of the capacity-controlled systems, are strongly dependent on electricity tariff, additional system cost, and period and duration of heat pump operation.

Performance of Add-On Heat Pump Water Heater (HPWH) Systems and Their Impacts on Electric Utility Loads

2010 ◽  
Author(s):  
Yahya I. Sharaf-Eldeen ◽  
Craig V. Muccio ◽  
Eric Gay
Keyword(s):  
Heat Pump ◽  
Energy Savings ◽  
Electric Energy ◽  
Electric Heating ◽  
Electric Utility ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Energy Output ◽  
Water Heater ◽  
Heat Pump Water Heater

This work involves measurements, analyses, and evaluations of the performance of add-on, Heat Pump Water Heater (HPWH) systems in residential and small commercial applications. Two air-source Heat Pump (HP) systems rated at 7,000- and 12,000-BTU (2.051- and 3.517-kWh), were utilized in this work. The two HPs were retrofitted to two 50-gallon (189.3 liters) electric-resistance storage water-heaters with their electric heating elements removed. A third, standard electric water-heater (EWH), was used for comparison. The testing set-up was fully instrumented for measurements of pertinent parameters, including inlet and outlet water temperatures, inlet and outlet air temperatures of the HPs, temperature and humidity of the air in the surrounding space, volume of water draws out of the storage heater tanks, as well as electric energy consumptions of the systems. Several performance measures were used in this work, including the Coefficient of Performance (COP), which is a measure of the instantaneous energy output in comparison with the energy input; Energy Factor (EF), which is an average measure of the COP taken over extended periods of time; and the First Hour Rating (FHR), which is a measure of the maximum volume of hot water that a storage type water-heater can supply to a residence within an hour. The results obtained clearly indicate that, HPWH systems are much more efficient as compared to standard EWHs. While the average value of the EF for a standard EWH is close to 1.0, the HPWH systems yield EFs averaging more than 2.00, resulting in annual energy savings averaging more than 50%. The results also showed that, HPWH systems are effective at reducing utility peak demand-loads, in addition to providing substantial cost savings to consumers.

scholarly journals Comparison of Transcritical CO2 and Conventional Refrigerant Heat Pump Water Heaters for Domestic Applications

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 479
Author(s):  
Ignacio Paniagua ◽  
Ángel Álvaro ◽  
Javier Martín ◽  
Celina Fernández ◽  
Rafael Carlier
Keyword(s):  
Heat Pump ◽  
Thermodynamic Cycle ◽  
Heat Pumps ◽  
Design Tool ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Ambient Conditions ◽  
Water Heater ◽  
Water Heaters

Although CO 2 as refrigerant is well known for having the lowest global warming potential (GWP), and commercial domestic heat pump water heater systems exist, its long expected wide spread use has not fully unfolded. Indeed, CO 2 poses some technological difficulties with respect to conventional refrigerants, but currently, these difficulties have been largely overcome. Numerous studies show that CO 2 heat pump water heaters can improve the coefficient of performance (COP) of conventional ones in the given conditions. In this study, the performances of transcritical CO 2 and R410A heat pump water heaters were compared for an integrated nearly zero-energy building (NZEB) application. The thermodynamic cycle of two commercial systems were modelled integrating experimental data, and these models were then used to analyse both heat pumps receiving and producing hot water at equal temperatures, operating at the same ambient temperature. Within the range of operation of the system, it is unclear which would achieve the better COP, as it depends critically on the conditions of operation, which in turn depend on the ambient conditions and especially on the actual use of the water. Technology changes on each side of the line of equal performance conditions of operation (EPOC), a useful design tool developed in the study. The transcritical CO 2 is more sensitive to operating conditions, and thus offers greater flexibility to the designer, as it allows improving performance by optimising the global system design.

Performance Comparison among Heat Pump Water Heaters Working with R32, R134a and the Mixture of R32/R134a

2012 ◽  
Vol 512-515 ◽  
pp. 1295-1298
Author(s):  
De Feng Ding ◽  
Shi Jie Liu ◽  
Chao Yu Zheng ◽  
Wen Sheng Yu ◽  
Wu Chen
Keyword(s):  
Power Consumption ◽  
Heat Pump ◽  
Average Power ◽  
Input Power ◽  
Performance Comparison ◽  
Coefficient Of Performance ◽  
Water Heater ◽  
Heat Pump Water Heater ◽  
Discharge Temperature ◽  
Average Power Consumption

A general air-source heat pump water heater originally designed to work with R134a was reconstructed as experimental rig for performance studies on systems using different refrigerants including R32, R134a and the mixture of R32/R134a which mass ratio is 1:5. Experimental results showed that the power consumption of the heat pump water heater charged individually with R32 would greatly exceed the system’s original pre-set maximum input power. When the leaving water temperature was increased from 18°C to 58°C, the average discharge temperature of the heat pump charged with R32/R134a mixture was 13.6% higher than that with R134a. The average power consumption of the heat pump with R134a was 253.5W less than that with R32/R134a mixture. However, the average COP (Coefficient of Performance) obtained by that with R32/R134a mixture was 0.83 higher than that with R134a.

Statistical Analyses on Usage of Water Heater in Urban Residential Buildings

2014 ◽  
Vol 521 ◽  
pp. 748-751
Author(s):  
Zhao Xia Zhou
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Residential Buildings ◽  
Water Heater ◽  
Water Heaters ◽  
Heat Pump Water Heater ◽  
Initial Cost ◽  
The Common ◽  
The Cost ◽  
Residential Water

A survey for water heater in urban residential buildings is carried in Wuhan. The results show that more than 40% subjects use solar energy water heat. More than 20% subjects point out the energy consumption of water heater should be decreased. There are about 24.8% subjects take initial cost as the first place when they chose water heater. 44.2% subjects know about heat pump water heater, but they could not buy it if the initial cost is too high. There are 84% subjects could select heat pump water heater when the cost is no more 20% high than the average price of the common water heaters. Moreover, the energy consumptions of residential water heaters are also investigated. The energy consumption characteristics of water heater in Wuhan are analyzed.

scholarly journals Heat Pump Water Heater For Cold Climate – Canada

2021 ◽  
Author(s):  
Afarin Amirirad
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Residential Buildings ◽  
Minimum Energy ◽  
Cold Climate ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Heater ◽  
Domestic Hot Water ◽  
Heat Pump Water Heater

Considering the large energy consumption of conventional water heaters in residential buildings, the performance of a new type of water heater has been characterized through conducting experiments and numerical modelling. The specific water heater investigated in this work benefits from heat absorption from the indoor air, denoted as the air source heat pump water heater (ASHPWH), and is located in the Archetype Sustainable Twin House B in Toronto. The experiments have been conducted under three different indoor conditions associated with temperature and humidity. The coefficient of performance (COP), which quantifies the ratio of heating capacity to the consumed power of ASHPWH, ranges between 1.5 and 5, depending on the indoor dry bulb and water inlet temperatures. A TRNSYS model of ASHPWH has been constructed based on the obtained experimental results and has subsequently been integrated with a TRNSYS model of the Archetype Sustainable House (ASH). The numerical results were verified with the experimental data. The model results suggests that after employing ASHPWH, the domestic hot water energy consumption reduces by 60.3% and 53.2% compared to the electric water heater in summer and winter respectively. Due to the energy absorption of ASHPWH from the indoor environment, the heating load of the ASH house increases while its cooling load decreases. Furthermore, the annual electricity consumption of the ASH house due to the required heating and cooling as well as the domestic hot water demand is reduced by 21.3%. Finally, as a consequence of employing ASHPWH, the energy cost and GHG emission were reduced respectively by 22% and 21.7%. By investigating the system in four other Canadian cities, it appears that Vancouver and Edmonton would have the maximum and minimum energy savings respectively.

scholarly journals Heat Pump Water Heater For Cold Climate – Canada

2021 ◽  
Author(s):  
Afarin Amirirad
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Residential Buildings ◽  
Minimum Energy ◽  
Cold Climate ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Water Heater ◽  
Domestic Hot Water ◽  
Heat Pump Water Heater

Considering the large energy consumption of conventional water heaters in residential buildings, the performance of a new type of water heater has been characterized through conducting experiments and numerical modelling. The specific water heater investigated in this work benefits from heat absorption from the indoor air, denoted as the air source heat pump water heater (ASHPWH), and is located in the Archetype Sustainable Twin House B in Toronto. The experiments have been conducted under three different indoor conditions associated with temperature and humidity. The coefficient of performance (COP), which quantifies the ratio of heating capacity to the consumed power of ASHPWH, ranges between 1.5 and 5, depending on the indoor dry bulb and water inlet temperatures. A TRNSYS model of ASHPWH has been constructed based on the obtained experimental results and has subsequently been integrated with a TRNSYS model of the Archetype Sustainable House (ASH). The numerical results were verified with the experimental data. The model results suggests that after employing ASHPWH, the domestic hot water energy consumption reduces by 60.3% and 53.2% compared to the electric water heater in summer and winter respectively. Due to the energy absorption of ASHPWH from the indoor environment, the heating load of the ASH house increases while its cooling load decreases. Furthermore, the annual electricity consumption of the ASH house due to the required heating and cooling as well as the domestic hot water demand is reduced by 21.3%. Finally, as a consequence of employing ASHPWH, the energy cost and GHG emission were reduced respectively by 22% and 21.7%. By investigating the system in four other Canadian cities, it appears that Vancouver and Edmonton would have the maximum and minimum energy savings respectively.

Development and Performance Validation of a Heat Pump Water Heater

2006 ◽  
Author(s):  
H. I. Abu-Mulaweh
Keyword(s):  
Heat Pump ◽  
Testing Procedure ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Experimental Measurements ◽  
Water Heater ◽  
Flow Rates ◽  
Heat Pump Water Heater ◽  
And Performance ◽  
Performance Validation

Heat pump water heater was designed and a prototype was developed and constructed. The performance of the heat pump water heater prototype is described by presenting some experimental test data. The experimental measurements include temperature, flow rates, and power consumption. The testing procedure consisted of evaluating the recovery rate and the coefficient of performance (COP) of the system. The results strongly indicate that heat pump water heater system design is very practical and it provides the consumer with a more efficient hot water heater alternative.

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.

Residential Water Heating Dehumidifier (WHD) With Devoted Dehumidification

2005 ◽  
Author(s):  
Aaron K. Ball ◽  
Chip W. Ferguson ◽  
Frank T. Miceli ◽  
Evelyn Baskin
Keyword(s):  
Heat Pump ◽  
Energy Use ◽  
Hot Water ◽  
Maximum Efficiency ◽  
Electric Resistance ◽  
Water Heating ◽  
Water Heater ◽  
Water Heaters ◽  
Heat Pump Water Heater ◽  
Residential Water

A new a dual-service dehumidifier water heater (WHD) appliance is being researched and developed by the authors. Prior research on a similar appliance, a heat pump water heater (HPWH), has demonstrated the unit’s increased performance and energy saving, and through collaboration, significant progress has been made toward developing the WHD into a potentially marketable product. The primary energy use in residential households is space conditioning (49%), and the second major energy use is hot water consumption. In DOE’s 2004 Buildings Data Book, 15.5 percent of residential energy utilization is consumed by water heating (DOE 2004, Table 1.2.3). The two major types of residential water heaters are direct gas fired (~55%) and electric resistance (~45%) (DOE 2004, Appliance Magazine 2005). The maximum efficiency of a standard electric resistance water heater is 1 (100%), and progress has been made to increase the efficiency of the current standard heaters to approximately 95 percent (DOE 2004, Table 5.10.6), which is roughly the maximum available with today’s technology. However, if the standard system is replaced by a Heat Pump Water Heater (HPWH), the performance can be increased by 140 percent (Zogg and Murphy 2004). The WHD operates as a HPWH while heating water and as a dedicated dehumidifier when water heating is not necessary. This paper presents the general design and laboratory testing results of a WHD. Preliminary performance data reveal coefficient of performances (COP) of approximately 2.2 during water heating. Further, market analysis has revealed that a potential need for this new technology is in regions with high humidity (Ashdown et al. 2004). These regions are primarily in the Northeast, Southeast and some coastal areas of the U.S. Current HPWH units do not have dedicated dehumidification and have a very small share of the residential water heat market. Of the 9.55 million residential water heaters sold in 2003 only about 2,000 of them were HPWHs (DOE 2004, Table 5.10.15).

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