scholarly journals Hybrid system solar collectors - heat pumps for domestic water heating

2019 ◽  
Vol 23 (6 Part A) ◽  
pp. 3675-3685
Author(s):  
Simon Marcic ◽  
Rebeka Kovacic-Lukman ◽  
Peter Virtic

This paper deals with the use of solar energy, heat pumps, and solar system-heat pump combinations for domestic water heating. The testing of solar tiles, flat plate collectors as an autonomous system, as well as flat plate collector-heat pump and solar tile-heat pump combinations, are presented. Black-coloured water absorbs solar radiation flows through solar tiles made of transparent polymethyl methacrylate (CH2C(CH3)COOCH3). At the same time, solar tiles are used as a roof covering and as a solar radiation collector. Hot water from solar tiles or a flat plate collector is directed to the heat pump, which increases the temperature of water entering the boiler heating coil. The heat of water heated in solar tiles or in flat plate collectors serves as a source of energy for the heat pump. Since the goal was realistically evaluate the efficiency of solar tiles in comparison with the flat plate collector, extensive measurements of both systems under identical condition were carried out. The experiments were carried out in rainy, cloudy, and clear weather.

2019 ◽  
Vol 4 (12) ◽  
pp. 41-47
Author(s):  
Md. Habibur Rahaman ◽  
Tariq Iqbal

Almost all single-family detached houses in Canada consume enormous electrical energy for space heating and domestic hot water (DHW) purposes. There are many possibilities to design an energy-efficient house. A solar water heating system can be used for domestic water and space heating. Water temperature can be kept constant always by connecting a heat pump or oil burner to the main tank because solar energy is intermittent. The sizing of solar photovoltaic and collector, tank, heat pump are essential to design an effective system based on the system energy consumption. The existing house is just a conventional house where space and water heating are provided by the grid electricity only. In this research, two possible ways of thermal energy storage systems have been designed for a residential single-family house with solar collector and solar photovoltaic. It is proved that the proposed PV based energy storage system is highly suitable considering lower cost, high output power, flexibility, and easy installation.


2016 ◽  
Vol 15 (2) ◽  
pp. 08
Author(s):  
O. R. S. Rodríguez ◽  
R. N. N. Koury ◽  
A. A. T. Maia

By increasing renewable energy demand, the use of solar energy has been widely investigated over the recent years. Brazil is a privileged country in terms of the levels of receivable solar radiation in almost all over its territory. However, as there are days when there is a deficit in solar energy, because the day be cloudy or rainy days, and for this reason, solar collectors need a support to contribute to the water heating to the desired temperature. In this work, an experimental study of a heat pump operated with R-134a, as an ancillary equipment for a solar water heating system in Belo Horizonte city has been accomplished. For this project, is used a set of electrical resistances for by a power control step, simulate historical annual values of solar radiation. In the results, it was observed that is achieved through the collection of solar energy the temperature of 45°C in the reservoir only in January, and the other eleven months is necessary to use the heat pump to achieve reach that temperature. With the heat pump operating in conditions similar to real conditions gave an average annual consumption of 137.65 kWh and a cost of R$ 60.61.


Author(s):  
Said Dini ◽  
Wellen G. Davison ◽  
John Vaccaro

Abstract A computerized data acquisition system for the solar hot water heating system located in the School of Engineering at Western New England College was designed and implemented. The system consists of three flat plate collectors located on the roof of the building facing south and inclinded at an angle of 40° with the horizontal, a heat exchanger, a storage tank, and an AST computer for data reduction, storage and analysis. The data collection and processing of this system was automated by interfacing a DAS-8 board located in the AST computer and a Metrabyte Exp-16 multiplexer amplifier board with 12 thermocouples and a pyranometer. The data acquisition program was written using GWBASIC along with DAS-8 commands. A program was also written to run the boards and do performance calculations. The program provides the solar radiation data, temperature distribution into the flat plate collector, temperatures in and out of the collector, useful energy gain and the efficiency of the collectors.


HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour

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.


Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 954 ◽  
Author(s):  
Hanne Kauko ◽  
Daniel Rohde ◽  
Armin Hafner

District heating enables an economical use of energy sources that would otherwise be wasted to cover the heating demands of buildings in urban areas. For efficient utilization of local waste heat and renewable heat sources, low distribution temperatures are of crucial importance. This study evaluates a local heating network being planned for a new building area in Trondheim, Norway, with waste heat available from a nearby ice skating rink. Two alternative supply temperature levels have been evaluated with dynamic simulations: low temperature (40 °C), with direct utilization of waste heat and decentralized domestic hot water (DHW) production using heat pumps; and medium temperature (70 °C), applying a centralized heat pump to lift the temperature of the waste heat. The local network will be connected to the primary district heating network to cover the remaining heat demand. The simulation results show that with a medium temperature supply, the peak power demand is up to three times higher than with a low temperature supply. This results from the fact that the centralized heat pump lifts the temperature for the entire network, including space and DHW heating demands. With a low temperature supply, heat pumps are applied only for DHW production, which enables a low and even electricity demand. On the other hand, with a low temperature supply, the district heating demand is high in the wintertime, in particular if the waste heat temperature is low. The choice of a suitable supply temperature level for a local heating network is hence strongly dependent on the temperature of the available waste heat, but also on the costs and emissions related to the production of district heating and electricity in the different seasons.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1576
Author(s):  
Piotr Jadwiszczak ◽  
Jakub Jurasz ◽  
Bartosz Kaźmierczak ◽  
Elżbieta Niemierka ◽  
Wandong Zheng

Heating and cooling sectors contribute to approximately 50% of energy consumption in the European Union. Considering the fact that heating is mostly based on fossil fuels, it is then evident that its decarbonization is one of the crucial tasks for achieving climate change prevention goals. At the same time, electricity sectors across the globe are undergoing a rapid transformation in order to accommodate the growing capacities of non-dispatchable solar and wind generators. One of the proposed solutions to achieve heating sector decarbonization and non-dispatchable generators power system integration is sector coupling, where heat pumps are perceived as a perfect fit. Air source heat pumps enable a rapid improvement in local air quality by replacing conventional heating sources, but at the same time, they put additional stress on the power system. The emissions associated with heat pump operation are a combination of power system energy mix, weather conditions and heat pump technology. Taking the above into consideration, this paper presents an approach to estimate which of the mentioned factors has the highest impact on heat pump emissions. Due to low air quality during the heating season, undergoing a power system transformation (with a relatively low share of renewables) in a case study located in Poland is considered. The results of the conducted analysis revealed that for a scenario where an air-to-water (A/W) heat pump is supposed to cover space and domestic hot water load, its CO2 emissions are shaped by country-specific energy mix (55.2%), heat pump technology (coefficient of performance) (33.9%) and, to a lesser extent, by changing climate (10.9%). The outcome of this paper can be used by policy makers in designing decarbonization strategies and funding distribution.


2016 ◽  
Author(s):  
Gabriel Agila ◽  
Guillermo Soriano

This research develops a detailed model for a Water to Water Heat Pump Water Heater (HPWH), operating for heating and cooling simultaneously, using two water storage tanks as thermal deposits. The primary function of the system is to produce useful heat for domestic hot water services according to the thermal requirements for an average household (two adults and one child) in the city of Quito, Ecuador. The purpose of the project is to analyze the technical and economic feasibility of implementing thermal storage and heat pump technology to provide efficient thermal services and reduce energy consumption; as well as environmental impacts associated with conventional systems for residential water heating. An energy simulation using TRNSYS 17 is carried to evaluate model operation for one year. The purpose of the simulation is to assess and quantifies the performance, energy consumption and potential savings of integrating heat pump systems with thermal energy storage technology, as well as determines the main parameter affecting the efficiency of the system. Finally, a comparative analysis based on annual energy consumption for different ways to produce hot water is conducted. Five alternatives were examined: (1) electric storage water heater; (2) gas fired water heater; (3) solar water heater; (4) air source heat pump water heater; and (5) a heat pump water heater integrated with thermal storage.


Author(s):  
Z. Sirkо ◽  
◽  
V. Korenda ◽  
I. Vyshnyakov ◽  
O. Protasov ◽  
...  

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.


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