scholarly journals Influence of the Thermal Energy Storage Strategy on the Performance of a Booster Heat Pump for Domestic Hot Water Production System Based on the Use of Low Temperature Heat Source

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6576
Author(s):  
Ximo Masip ◽  
Emilio Navarro-Peris ◽  
José M. Corberán
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Energy Recovery ◽  
Hot Water ◽  
Water Volume ◽  
Water Production ◽  
Domestic Hot Water ◽  
Temperature Heat ◽  
Variable Water

Energy recovery from a low temperature heat source using heat pump technology is becoming a popular application. The domestic hot water demand has the characteristic of being very irregular along the day, with periods in which the demand is very intensive and long periods in which it is quite small. In order to use heat pumps for this kind of applications efficiently, the proper sizing and design of the water storage tank is critical. In this work, the optimal sizing of the two possible tank alternatives, closed stratified tank and variable-water-volume tank, is presented, and their respective performance compared, for domestic hot water production based on low temperature energy recovery in two potential applications (grey water and ultra-low temperature district heating). The results show that the efficiency of these kind of systems is very high and that variable-water-volume tanks allow a better use of the energy source, with an 8% higher exergy efficiency and around 3% better seasonal performance factor (SPF), being able to provide similar comfort levels with a smaller system size.

The Optimal Peak-Adjusting Parameters of Low-Temperature Heat Source Heating

Solar Energy ◽  
2005 ◽  
Author(s):  
Ronghua Wu ◽  
Chenghu Zhang ◽  
Dexing Sun
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Water System ◽  
Weather Conditions ◽  
Integrated System ◽  
Hot Water ◽  
Cold Weather ◽  
Design Parameters ◽  
Temperature Heat

The integrated low and high temperature heating water system consists of heat pump heat source and boiler heat source. The heat pump heat source abstract heat from low temperature heat source and produce hot water up to 65°C. During mild weather, the 65°C hot water is sufficient for building heating. During cold weather conditions, the boiler heat source will have to be used to produce hot water at 90°C or higher to satisfy the building comfort. To improve the system economy, the integrated system has to maximize the use of the low temperature heat source since it is free. This paper presents a theoretical models and analysis to optimize the system design parameters.

scholarly journals Performance Assessment of Example PVT-Systems

2020 ◽  
Author(s):  
Maike Schubert ◽  
Daniel Zenhäusern
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Performance Indicators ◽  
Control Strategies ◽  
Climatic Conditions ◽  
Hot Water ◽  
Water Production ◽  
Swimming Pools ◽  
Domestic Hot Water ◽  
Financial Perspective

The performance of 26 PVT-Systems was analysed and compared in IEA-SHC Task 60. The systems are located in countries with different climatic conditions. The applications range from direct domestic hot water production and heating of public swimming pools to heat pump systems with PVT as the main heat source of the heat pump. The Key Performance Indicators (KPIs) determined for the different PVT solutions give the possibility to compare the systems despite their diversity. The goal was to show the potential of PVT collectors in different fields of application. The results show that the integration of PVT collectors in different kinds of well-dimensioned systems leads to competitive solutions, both from an energy and a financial perspective. Additionally the answers to a survey about control strategies for PVT systems, showing some main problems and possible solutions, are summarised.

scholarly journals Analysis and Comparison of Some Low-Temperature Heat Sources for Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1853 ◽  
Author(s):  
Pavel Neuberger ◽  
Radomír Adamovský
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Ambient Air ◽  
Heat Transfer Fluid ◽  
Heat Sources ◽  
Ground Heat Exchangers ◽  
Temperature Heat

The efficiency of a heat pump energy system is significantly influenced by its low-temperature heat source. This paper presents the results of operational monitoring, analysis and comparison of heat transfer fluid temperatures, outputs and extracted energies at the most widely used low temperature heat sources within 218 days of a heating period. The monitoring involved horizontal ground heat exchangers (HGHEs) of linear and Slinky type, vertical ground heat exchangers (VGHEs) with single and double U-tube exchanger as well as the ambient air. The results of the verification indicated that it was not possible to specify clearly the most advantageous low-temperature heat source that meets the requirements of the efficiency of the heat pump operation. The highest average heat transfer fluid temperatures were achieved at linear HGHE (8.13 ± 4.50 °C) and double U-tube VGHE (8.13 ± 3.12 °C). The highest average specific heat output 59.97 ± 41.80 W/m2 and specific energy extracted from the ground mass 2723.40 ± 1785.58 kJ/m2·day were recorded at single U-tube VGHE. The lowest thermal resistance value of 0.07 K·m2/W, specifying the efficiency of the heat transfer process between the ground mass and the heat transfer fluid, was monitored at linear HGHE. The use of ambient air as a low-temperature heat pump source was considered to be the least advantageous in terms of its temperature parameters.

scholarly journals Experimental and numerical study of the domestic hot water production with PV panels and a heat pump

2019 ◽  
Vol 111 ◽  
pp. 01066
Author(s):  
F. J. Aguilar ◽  
D. Crespí ◽  
P. V. Quiles
Keyword(s):  
Heat Pump ◽  
Computer Model ◽  
Numerical Study ◽  
Hot Water ◽  
Water Production ◽  
Storage Tanks ◽  
European Standard ◽  
Photovoltaic Panels ◽  
Domestic Hot Water ◽  
Experimental Works

This article presents an experimental and modelling work which uses a compact domestic hot water heat pump (DHW-HP) that is simultaneously powered from photovoltaic panels (PV) and from the grid. Results from more than 240 days of experimental works have been used in order to develop and to validate the computer model of the system. The program, implemented in MATLAB, is computationally ‘light’ enough to allow mid-term simulations yet also detailed enough to accurately and coherently portray stratification within thermal storage tanks. Finally, as an example of the model capabilities, it has been used to simulate a domestic hot water tapping cycle from the European Standard EN 16147.

Application Study of Newly Developed Turbo Heat Pump for 130 Degrees Celsius Water for an Industrial Process

2011 ◽  
Author(s):  
Shuichi Umezawa ◽  
Haruo Amari ◽  
Hiroyuki Shimada ◽  
Takashi Matsuhisa ◽  
Ryo Fukushima ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
High Efficiency ◽  
Industrial Process ◽  
Application Study ◽  
Hot Air ◽  
Heat Demand ◽  
Temperature Heat

This paper reports application study of newly developed turbo heat pump for 130 degrees Celsius (°C) water for an industrial process in an actual factory. The heat pump is characterized by high efficiency and large heat output, by using a state-of-the-art turbo compressor. The heat pump requires a low temperature heat source in order to achieve high efficiency. The heat demand is for several drying furnaces in the factory, which requires producing hot air of 120 °C. The heat exchanger was designed to produce the hot air. Experiments were conducted to confirm the performance of the heat exchanger under a reduced size of the heat exchanger. Low temperature heat sources are from both exhaust gas of the drying furnaces and that of an annealing furnace. The heat exchangers were also designed to recover heat of the exhaust gas from the two types of furnace. A thermal storage tank was prepared for the low temperature heat source, and for adjusting the time difference between the heat demand and the low temperature heat source. The size of the tank was determined by considering the schedule of furnaces operations. As a result of the present study, it was confirmed that the heat pump was able to satisfy the present heat demand while retaining high efficiency. Primary energy consumption and CO2 emission of the heat pump were calculated on the basis of the present results in order to compare them with those of the boilers.

Experimental Study of a Laminar Flow Solid Desiccant Dehumidifier Driven by a Low Temperature Heat Source

2016 ◽  
Vol 819 ◽  
pp. 361-365 ◽  
Author(s):  
Seung Jin Oh ◽  
Kyaw Thu ◽  
Muhammad Wakil Shahzad ◽  
Wongee Chun ◽  
Kim Choon Ng
Keyword(s):  
Experimental Study ◽  
Low Temperature ◽  
Laminar Flow ◽  
Heat Source ◽  
Silica Gel ◽  
Average Diameter ◽  
Hot Water ◽  
Dry Air ◽  
Temperature Heat ◽  
Adsorption Desorption

In this paper, an experimental study of a laminar flow solid desiccant dehumidifier has been presented. The cyclic steady state performance of adsorption-desorption processes was analyzed at various heat source temperatures and typical ambient humidity conditions in tropics. The desiccant dehumidification system consists of two beds filled with silica gel, two heat exchangers operating at 30 oC and 80 oC respectively, three humidity stations for measurement of the temperature and humidity conditions of the system and a blower to make airflow throughout the system. Type-RD silica gel of 0.3 mm average diameter was used as the working desiccant in the dehumidification system. This system has no moving parts rendering less maintenance compared with a rotary type. It is also energy-efficient means of dehumidification by adsorption process with low temperature heat source as compared to the conventional methods. As a result, it was observed the humidity ratio of inlet air is reduced from 24 g/kg of dry air to about 17 g/kg of dry air. Concomitantly, hot water at 80 oC is used to regenerate the adsorbent.

The Combined Solar with a Dual Heat Source Heat Pump Applied in a Greenhouse Heating System - An Operation Optimization of Water Source Heat Pump

2014 ◽  
Vol 541-542 ◽  
pp. 942-948
Author(s):  
Xian Peng Sun ◽  
Zhi Rong Zou ◽  
Yue Zhang
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Water Source ◽  
Heating System ◽  
Hot Water ◽  
Inlet Temperature ◽  
Pump System ◽  
Operation Optimization ◽  
Temperature Heat ◽  
The Impact

Based on the finite-time thermodynamic theory, an operation optimization, of water source heat pump in the combined solar with a dual heat source heat pump which is applied in a greenhouse heating system, is made. According to the ε-NTU method and entropy theory, heat exchange and balance equations are obtained. The function relationship between COP and the indoor temperature Tn, the ambient temperature Ta, low temperature heat source inlet temperature Tie and high temperature heat source inlet temperature Tic is also obtained. By means of programming, the impact of parameters on the COP and the way of regulating this water source heat pump system are presented in this article. The results show that: when a separate water source heat pump is running, by adjusting the hot water temperature and the match status of each indoor heating system, the energy-saving operation can be realized.

Determination of Heat Transfer Characteristics of Solar Thermal Collectors as Heat Source for a Residential Heat Pump

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Maarten G. Sourbron ◽  
Nesrin Ozalp
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Solar Collector ◽  
Heat Transfer Characteristics ◽  
Pump System ◽  
Heat Pump System ◽  
Temperature Heat

With reducing energy demand and required installed mechanical system power of modern residences, alternate heat pump system configurations with a possible increased economic viability emerge. Against this background, this paper presents a numerically examined energy feasibility study of a solar driven heat pump system for a low energy residence in a moderate climate, where a covered flat plate solar collector served as the sole low temperature heat source. A parametric study on the ambient-to-solarfluid heat transfer coefficient was conducted to determine the required solar collector heat transfer characteristics in this system setup. Moreover, solar collector area and storage tank volume were varied to investigate their impact on the system performance. A new performance indicator “availability” was defined to assess the contribution of the solar collector as low temperature energy source of the heat pump. Results showed that the use of a solar collector as low temperature heat source was feasible if its heat transfer rate (UA-value) was 200 W/K or higher. Achieving this value with a realistic solar collector area (A-value) required an increase of the overall ambient-to-solarfluid heat transfer coefficient (U-value) with a factor 6–8 compared to the base case with heat exchange between covered solar collector and ambient.

scholarly journals Thermodynamic analysis of the heat pump steam system with medium-low temperature heat source

2021 ◽  
Vol 7 ◽  
pp. 266-278
Author(s):  
Shuaiqi Li ◽  
Shihui He ◽  
Wenji Song ◽  
Zipping Feng
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
Thermodynamic Analysis ◽  
Temperature Heat ◽  
Steam System
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