Heat Pumps for Energy Saving of Building Hot Water Supply

2011 ◽  
Vol 347-353 ◽  
pp. 587-590
Author(s):  
Qing Hai Luo ◽  
Zheng Zuo
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Water Supply ◽  
Energy Saving ◽  
Heat Pump ◽  
Heat Pumps ◽  
Hot Water ◽  
Low Energy ◽  
Water Heaters ◽  
Hot Water Supply

This paper analyzes the energy consumption of hot water supply in buildings and the insurmountable shortcoming of low energy efficiency of conventional water heaters, and investigates the progress and problems of developing heat pump water heaters. It is pointed out that developing of heat pump water heaters is one of the efficient approaches to improve the energy efficiency of hot water supply.

scholarly journals Prospect for the using of heat pumps for heating of buildings in enterprise

2020 ◽  
Author(s):  
Z. Sirkо ◽  
◽  
V. Korenda ◽  
I. Vyshnyakov ◽  
O. Protasov ◽  
...  
Keyword(s):  
Water Supply ◽  
Heat Pump ◽  
Thermal Energy ◽  
Alternative Energy ◽  
Thermodynamic Cycle ◽  
Heat Pumps ◽  
The State ◽  
Hot Water ◽  
Alternative Energy Sources ◽  
Hot Water Supply

Heat pump - a device for transferring thermal energy from a source of low potential thermal energy to a consumer with a higher temperature. The thermodynamic cycle of a heat pump is similar to a refrigerating machine. Depending on the principle of operation, heat pumps are divided into compression and absorption. The most commonly used compression heat pumps. In recent years, numerous publications on the use of heat pump technology in heating and hot water supply facilities of various spheres - from individual homes to residential neighborhoods have appeared in various media. The authors of the publication have many years of experience in joint scientific and technical cooperation with leading technical universities and industrial organizations in the field of development and practical use of heat pump technology. The authors analyze the possibilities of introducing heat pumps at enterprises and organizations of the State Reserve System of Ukraine. It has been shown that the amount of expenses in comparison with central heating or operation of gas and electric boilers of similar power is several times smaller. It is noted that the implementation of heat pumps is a promising direction in the use of alternative energy sources to meet the heating, ventilation and hot water supply needs of buildings. The payback period from the introduction of heat pumps at enterprises is 4-9 years, depending on the location of the object and the type of source of low-temperature heat. The article meets the requirements of the State Tax Code of Ukraine and can be recommended for publication.

scholarly journals Nontargeted vs. Targeted vs. Smart Load Shifting Using Heat Pump Water Heaters

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7574
Author(s):  
Manasseh Obi ◽  
Cheryn Metzger ◽  
Ebony Mayhorn ◽  
Travis Ashley ◽  
Walter Hunt
Keyword(s):  
Water Supply ◽  
Heat Pump ◽  
Energy Use ◽  
Control Strategies ◽  
Lessons Learned ◽  
Hot Water ◽  
Third Party ◽  
Load Shifting ◽  
Water Heaters ◽  
Hot Water Supply

Deployment of CTA-2045–enabled devices is increasing in the U.S. market. These devices allow utilities or third-party aggregators to control appliance energy use in homes, and could also be applied to end uses in small commercial buildings. This study focuses on a field study using CTA-2045–enabled water heaters to shift electric load off the peak and toward periods when renewable resources are more prevalent (e.g., near noon for solar resources and near midnight for wind resources). The following load shifting strategies were compared to understand effects on the aggregate load-shifting capabilities of Heat Pump Water Heaters (HPWHs) and on consumer hot water supply: non-targeted (traditional), targeted (grouped, with different shifting schedules) and “smart” (adaptive control commands). The results of this study show that targeted and smart control strategies yield significantly more load-shifting potential from a population of water heaters than the non-targeted approach without sacrificing hot water supply to occupants. However, as control commands become more aggressive, aggregators may face challenges in meeting consumer hot water demand. The findings and lessons learned can benefit electric utilities and inform updates to manufacturer controls and communications standards. The data collected may also be useful for developing and validating HPWH models.

DETERMINING THE PROFITABILITY OF GREENHOUSE ELECTROTECHNOLOGIES: A MODELING APPROACH

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Water System ◽  
Heat Pumps ◽  
Hot Water ◽  
Pump System ◽  
Heat Pump System ◽  
Artificial Lighting ◽  
Hot Air ◽  
Marketable Fruit

The main objective of this research was to produce a simulated model that permitted the evaluation of operating costs of commercial greenhouse tomato growers with respect to heating methods (hot air, hot water, radiant and heat pumps) and the use of artificial lighting for 1991 and 1992. This research showed that the main factors that negatively influence profitability were energy consumption during cold periods and the price of tomatoes during the summer season. The conventional hot water system consumed less energy than the heat pump system and produced marketable fruit yields similar to those from the heat pump system. The hot water system was generally more profitable in regards to energy consumption and productivity. Moreover, investment costs were less; therefore, this system gives best overall financial savings. As for radiant and hot air systems, their overall financial status falls between that of the hot water system and the heat pump. The radiant system proved to be more energy efficient that the hot air system, but the latter produced a higher marketable fruit yield over the 2-year study.

Riqualificazione energetica e bioedilizia in Italia: lo stato dell'arte

2012 ◽  
pp. 74-88
Author(s):  
Livio de Santoli
Keyword(s):  
Energy Efficiency ◽  
Renewable Energy ◽  
Energy Consumption ◽  
Fossil Fuels ◽  
Building Materials ◽  
Heat Pumps ◽  
Building Envelope ◽  
International Standards ◽  
Solar Panels ◽  
Water Heaters

Building sustainability, in term of energy efficiency, low-impact building materials, renewable energy, has experienced significant growth during the past years. In response to the growing dependence on fossil fuels and importations, due in part to the increase of energy consumption in the residential sector (in 2009 46,9 Mtep, 3% more than 2008) and the recent European directives (i.e. EU 2009/28/CE) requiring CO2 emissions cut of up to 13% in 2020, there is interest in promoting energy efficiency and renewable energy technologies, which are suitable for residential applications. In this paper we present an overview on actions related to minimization of buildings energy consumption in Italy. Prevalent line of action is to improve the energy performances of building envelope (Dlgs 192/05) using insulated frames, walls and roofs and replacing heat generators with condensing boilers. In addition to national directives, ONRE Report 2011 (National Observatory on building regulations) shows that 831 Municipalities (10% more than 2010) establish mandatory targets for insulation, photovoltaic solar panels, solar water heaters, heat pumps use, correct buildings orientation, saving of water resource and local materials use. In addiction an efficient energy rating of the buildings could promote the spread of energy efficiency measurement and consequently facilitate their implementation. The new energy rating system should meet international standards, regarding environment and energy aspects, and respect territorial needs.

Studies of Heat Pumps Using Direct Expansion Type Solar Collectors

Solar Energy ◽  
2003 ◽  
Author(s):  
Sadasuke Ito ◽  
Naokatsu Miura ◽  
Yasushi Takano
Keyword(s):  
Heat Pump ◽  
Thermal Performance ◽  
Pressure Loss ◽  
Heat Pumps ◽  
Hot Water ◽  
Photovoltaic Module ◽  
Direct Expansion ◽  
Reduced Pressure ◽  
In Series ◽  
Hot Water Supply

A photovoltaic and thermal hybrid panel which was made of an aluminum roll -bond panel with a photovoltaic module on the surface was developed recently for use as an evaporator of a heat pump for residential hot water supply and room heating.1) Pressure loss of the refrigerant at the evaporator was large. Therefore, in the present study, shapes of the inlet and the outlet of the panel were modified to reduce pressure loss; also, thermal performance of the heat pump which adopted three evaporator panels connected in series was examined. Total area of the panels was about 1.9 m2 and the rated capacity of the compressor was 250 W. These modifications reduced pressure loss and improved thermal performance. The effect of the location of the feeler bulb on performance of the heat pump was also examined. It was inferred that the feeler bulb fixed on the tube at the outlet of the evaporator should be as close as possible to the evaporator outlet.

scholarly journals A Study on the Performance of a Cascade Heat Pump for Generating Hot Water

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4313 ◽  
Author(s):  
Boahen ◽  
Choi
Keyword(s):  
Heat Exchanger ◽  
Energy Saving ◽  
Heat Pump ◽  
Heat Pumps ◽  
Hot Water ◽  
Research Interest ◽  
Coefficient Of Performance ◽  
Energy Saving Potential ◽  
Heating Capacity

The use of cascade heat pumps for hot water generation has gained much attention in recent times. The big question that has attracted much research interest is how to enhance the performance and energy saving potential of these cascade heat pumps. This study therefore proposed a new cycle to enhance performance of the cascade heat pump by adopting an auxiliary heat exchanger (AHX) in desuperheater, heater and parallel positions at the low stage (LS) side. The new cascade cycle with AHX in desuperheater position was found to have better performance than that with AHX at heater and parallel positions. Compared to the conventional cycle, heating capacity and coefficient of performance (COP) of the new cascade cycle with AHX in desuperheater position increased up to 7.4% and 14.9% respectively.

Evaluation of Passive Anti-Fouling Technology Applied to CO2 Heat Pump Water Heaters

2014 ◽  
Author(s):  
Portia Murray ◽  
Stephen J. Harrison ◽  
Ben Stinson
Keyword(s):  
Heat Transfer ◽  
Water Supply ◽  
Heat Pump ◽  
Hot Water ◽  
Normal Operation ◽  
Mineral Deposits ◽  
Reverse Direction ◽  
Water Tank ◽  
Flow Rates ◽  
Water Heaters

Heat pump water heaters are increasing in popularity due to their increased energy efficiency and low environmental impact. This paper describes the experimental testing of a transcritical CO2 heat pump water heater at Queen’s University. A modified 4.5 kW Eco-Cute unit was studied. It sourced heat from a constant temperature water supply and rejected the heat to a 273 litre hot water tank through a gas-cooler. The high temperatures that occur in the gas-cooler of this unit make it ideally suited for natural convection, (i.e., thermosyphon) circulation on the potable water side. This has the potential to reduce pumping power, simplify system operation and design, and increase thermal stratification in the hot water storage tank. This configuration, however, is susceptible to the accumulation of sediments, scale and mineral deposits (i.e., fouling) in geographic regions where high mineral deposits may be present in the water supply. To counteract fouling in these cases, a passive back-flushing system was proposed to prevent the accumulation of deposits on the heat transfer surfaces of the gas-cooler. As hot water is drawn from the system, the cold “mains” supply water is directed through the gas-cooler in the reverse direction of normal operation, scouring the heat transfer surfaces and dissolving deposits of inverse-soluble salts which are a major contributor to fouling on hot heat transfer surfaces. The gas-cooler used was a specially designed unit that, although offering high performance in a compact unit, may be susceptible to the fouling and blockage of the heat transfer passages when used at thermosyphon flow rates. Experiments were conducted to evaluate the effects of the back-flush operation on heat pump performance (i.e., COP) and operation. These were conducted under controlled laboratory conditions, at a range of draw flow rates and temperatures, and are summarized in this paper.

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.

scholarly journals Optimization of a Wood Pellet Boiler System Combined with CO2HPs in a Cold Climate Area in Japan

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5531 ◽  
Author(s):  
Taro Mori ◽  
Yusuke Iwama ◽  
Hirofumi Hayama ◽  
Emad Mushtaha
Keyword(s):  
Energy Consumption ◽  
Water Supply ◽  
Co2 Emissions ◽  
Primary Energy ◽  
Cold Climate ◽  
Hot Water ◽  
Water Volume ◽  
Primary Energy Consumption ◽  
Wood Pellet ◽  
Hot Water Supply

Hot water supply is one of the leading consumers of energy in the building sector in cold climate areas. The use of woody biomass is effective in reducing CO2 emissions in hot-water supply systems. This report deals with a system that combines a wood pellet boiler (PB) and a heat pump system with CO2 (CO2HP) that is used in a facility for disabled people. The following research was conducted. The operation of a hybrid system combining a PB and CO2HPs was investigated. While operating the system, four specific operations were developed as countermeasures to save on costs and reduce system troubles while reducing CO2 emissions. The processes and results are introduced. Numerical simulations were carried out to optimize the operation. The hot water temperature, water volume, and hot water loads were simulated. The influence of the water volume ratio on the cost and primary energy consumption under the requirements for safe system operation was studied. The regional economic ripple effects (REREs) of this system were studied. The wood pellet boiler is not only a measure for reducing primary energy consumption but can also play an important role in a regional economy for sustainable development in countries that import energy resources such as Japan.

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