scholarly journals Mathematical modeling of a heat pump and its operation modes

2020 ◽  
Vol 216 ◽  
pp. 01165
Author(s):  
Mehriya Koroli ◽  
Oybek Ishnazarov

The paper describes a mathematical model of the heat pump system of autonomous heat supply. Calculations of the temperature at the outlet of the pipeline and the heat pump are given; heat generation and heater condition.

Author(s):  
Masahito Oguma ◽  
Takeshi Matsumoto ◽  
Takao Kakizaki

Feasibility of a ground source heat pump (GSHP) system with pile heat exchangers for use in houses is evaluated through a numerical simulation. This GSHP system differs from ordinary borehole-type GSHP systems because short foundation piles installed at close intervals are used as heat exchangers. It is shown that the annual heat supply provided by this GSHP system is able to satisfy the demand of a house due to the air-source exchange at ground surface.


2021 ◽  
Vol 289 ◽  
pp. 05005
Author(s):  
Ivan Sokolov ◽  
Artem Ryzhenkov ◽  
Elizaveta Tyabut

The climatic conditions in Moscow limit to a certain extent the utilization of renewable energy sources for heat supply. Long heating period, relatively low average daily sunshine hours during heating period, and low outside temperatures act as barriers to realising the full potential of renewable energy sources. The paper presents an evaluation of feasibility and effectiveness of using various renewable energy sources in the heat supply system of Block 23 of the National research university «MPEI». The system arrangement for heat supply of the building with renewable energy sources is described. Experimental data have been obtained on the basis of this system. The calculated time dependences of building heat consumption and heat pump system (HPS) outputs are given. In addition, for the air-source heat pump system, the dependence on the outdoor temperature is given. Values of HPS efficiency indices are also presented. A comparative analysis of the efficiency of air-source HPS and liquid-to-liquid HPS with a geothermal circuit in winter conditions is carried out.


2018 ◽  
Vol 22 (5) ◽  
pp. 2203-2213 ◽  
Author(s):  
Magdalena Wolf ◽  
Thomas Detzlhofer ◽  
Tobias Proll

In this paper, the thermodynamic and economic efficiency of three different heat supply processes are compared, based on exergy flows and costs of heat. A gas turbine process with a heat recovery boiler, a gas and steam turbine combined cycle process and a high temperature heat pump system recovering waste heat are analysed. The aim is to provide heat as 4 bar(abs) saturated steam. The economic analysis bases on the comparison of the consumption-related costs of heat, the capital-related costs of heat, and the operation-related costs of heat. The results show that the heat pump system has higher exergetic efficiency than the gas turbine or the gas turbine combined cycle process. For the consumption related costs, the economic calculation shows that the operation of a heat pump, working with a coefficient of performance of four and for a natural gas price of 25 ?/MWh, is the cheapest way of heat production as long as the electricity price is lower than 45 ?/MWh. For the period from January 2013 until June 2016 the total costs of heat, based on real gas and electricity prices from the European Energy Exchange, are calculated and analysed. The results show that the share of heat provided by the heat pump system varies between 45% and 76%. Especially in 2013 and 2014, the economic conditions for operating heat pumps were very good. Since October 2015 the natural gas prices have seen a decrease which favours industrial heat supply with combined heat and power systems.


2022 ◽  
Vol 308 ◽  
pp. 118204
Author(s):  
Christian Vering ◽  
Laura Maier ◽  
Katharina Breuer ◽  
Hannah Krützfeldt ◽  
Rita Streblow ◽  
...  

2011 ◽  
Vol 138-139 ◽  
pp. 305-309
Author(s):  
Chao Zhang ◽  
Xiao Dan Zhao ◽  
Guang Hui Zhou

The heat pump technology which is as an effective energy-saving technology has attracted more and more attentions. A novel solar-air dual-source heat pump system which could synchronously use two heat sources has been provided. In this paper, the mathematical model of the new heat pump system has been built and the calculation accuracy of the mathematical model has been proved. Based on a novel solar-air dual-source heat pump system, the mathematical models of the thermophysical parameters of working fluids, compressor, capillary, condenser, evaporator, and heat pump system have been established. The distribution parameter method has been adopted in the mathematical models of condenser and evaporator. Three operation modes of the novel solar-air dual-source heat pump system have been simulated. The simulated results and the experimental results have been compared. The experiments of the novel solar-air dual-source heat pump system have been accomplished in the constant temperature and humidity laboratory. The compared results show that the error is less than 10%.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1028 ◽  
Author(s):  
Agata Rijs ◽  
Tomasz Mróz

The vapor compression heat pumps are very popular solutions regarding heat supply systems of modern, low energy buildings. It is partly due to the fact that they are treated as a sustainable heat supply. The question arises: Can a vapor compression heat pump be treated as a sustainable heat supply? To answer this question; the exergy model of a heat pump system operation has been proposed. The proposed model has been employed for evaluation of exergy efficiency of an existing heat supply system equipped with two heat pumps installed in an educational building located on the campus of Poznan University of Technology, Poznan, Poland. The analysis shows that the system exergy efficiency decreases with an increase in outdoor temperature and its values are in the range of 10.9% to 42.0%. The primary exergy efficiency, which considers the conversion of fossil fuel into electricity, is on average 3.2 times lower than the system exergy efficiency for the outdoor temperature range of −9 °C to 11 °C. The performed analysis allowed for the identification of a set of solutions that may increase the exergy and primary exergy efficiency of the system. The first solution is to cover a part of the electricity demand by a renewable energy source. The second proposition is to apply a low-temperature emission system for heating. The third idea is to apply a district heating network as the heat supply instead of the heat pump. The conclusion is that the exergy performance of systems with heat pumps is rather poor because they generate low-quality heat from high-quality electricity. The best way to improve the primary exergy efficiency of a heat pump system is to power the system by electricity generated from a renewable energy source.


2012 ◽  
Vol 472-475 ◽  
pp. 637-640
Author(s):  
Cheng Hu Zhang ◽  
Na Meng ◽  
De Xing Sun

The extremely poor sewage quality could make the sewage heat utilization difficult. The paper introduces the content and distribution property of the sewage dirt. For the dirt properties and project experience, it proposes the two basic points of the anti-blocking technique in sewage source heat pump system: filtering surface continuous regeneration and dirt continuous reduction and the request for filtering pore size parameters. It also describes the principle of filtering surface hydraulic continuous regenerative technique and establishes its mathematical model and design method of the device. The calculation and application result indicates that filtering surface hydraulic continuous regenerative technique can guarantee the filtering effect and operation flow stable.


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