The Possibility of Using the Ground as a Seasonal Heat Storage: The Numerical Study

2004 ◽  
Author(s):  
Pawel Olszewski
Keyword(s):  
Solar Energy ◽  
Heat Storage ◽  
Numerical Study ◽  
Storage System ◽  
Heating System ◽  
Numerical Code ◽  
Space Heating ◽  
Solar Collectors ◽  
Seasonal Heat ◽  
The One

Humankind can effectively utilize only part of the solar energy reaching a surface of the Earth. It is due to the low density of the solar radiation and its unfavorable distribution. The majority of solar energy falls to the low latitude countries, where space-heating requirements are marginal. In these countries the solar heat is used for preparing water for washing or cleaning purposes, and this process works in one, or — maximum — a few daily cycles. In countries located at higher latitudes, where space heating is necessary in cold months, the current solar energy is insufficient to meet the space heating demand. The heat storage in deep layer of the ground is the one of possible way for solution of this problem. During the heating season, energy storage is discharged supplying the heat pomp cooperating with domestic heating system and during the summer months the storage can be charged by fluid heated in solar collectors. The main aim of presented research was analysis of using the ground layer as a heat storage system in the countries located in higher latitudes. The first variable taken into consideration was the output temperature of water leaving the solar collectors. The temperature distribution in the ground depends on the inlet water temperature, primary heated in the solar collectors, and forced into vertical boreholes. The temperature field in the ground was calculated using the duFort-Frankel finite-difference numerical method. A numerical code for 3D time dependent storage simulation has been created. The next step of analysis was calculation of waters’ temperature at the borehole output during cold months when the ground storage is discharged. This water works as a low-temperature reservoir of the heat pomp supplying the dwelling heating system. The solution of the problem is focused on an optimization of all parameters for the most efficient utilization of energy stored in the ground. The numerical genetic algorithms are scheduled to use to achieve this target.

scholarly journals Exergy Analysis of Phase-Change Heat-Storage Coupled Solar Heat Pump Heating System

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5552
Author(s):  
Chuanhui Zhu ◽  
Shubin Yan ◽  
Xiaodong Dong ◽  
Wei Zhang ◽  
Biyi Huang ◽  
...  
Keyword(s):  
Solar Energy ◽  
Phase Change ◽  
Heat Pump ◽  
Exergy Analysis ◽  
Heat Storage ◽  
Heating System ◽  
Exergy Loss ◽  
Solar Collectors ◽  
Solar Heat ◽  
Northern Regions

With the rapid development of industrialization, the excessive use of fossil fuels has caused problems such as increased greenhouse gas emissions and energy shortages. The development and use of renewable energy has attracted increased attention. In recent years, solar heat pump heating technology that uses clean solar energy combined with high-efficiency heat pump units is the development direction of clean heating in winter in northern regions. However, the use of solar energy is intermittent and unstable. The low-valley electricity policy is a night-time electricity price policy. Heat pump heating has problems such as frosting and low efficiencies in cold northern regions. To solve these problems, an exergy analysis model of each component of a phase-change heat-storage coupled solar heat pump heating system was established. Exergy analysis was performed on each component of the system to determine the direction of optimization and improvement of the phase-change heat-storage coupled solar heat pump heating system. The results showed that optimizing the heating-end heat exchanger of the system can reduce the exergy loss of the system. When the phase-change heat-storage tank meets the heating demand, its volume should be reduced to lower the exergy loss of the tank heat dissipation. Air-type solar collectors can increase the income exergies of solar collectors.

scholarly journals Simulation and Analysis of Influencing Factors of Solar Energy Inter-seasonal Soil Heat Storage

2021 ◽  
Vol 293 ◽  
pp. 03018
Author(s):  
Ping Lin ◽  
Xiangzhi Yao ◽  
Yunpeng Bai
Keyword(s):  
Solar Energy ◽  
Heat Storage ◽  
Storage System ◽  
Great Influence ◽  
Storage Period ◽  
Ground Temperature ◽  
Storage Effect ◽  
Practical Engineering ◽  
Seasonal Heat ◽  
Spacing Length

Taking an office building in Jinan as an example, the simulation model of solar inter-seasonal soil heat storage was established by TRNSYS software, and the variation law of ground temperature in the heat storage period was analyzed. From the perspective of ground temperature change, the influence of the spacing, length, number of drilling wells and area of solar collector on the heat storage effect was analyzed. The results showed that the soil temperature increased rapidly at the beginning of heat storage, and then the temperature rise rate gradually slowed down. The ground heat exchanger spacing, length, number of drilling and collector area will have a great influence on the solar energy seasonal heat storage effect. Therefore, in practical engineering applications, for the solar inter-seasonal soil heat storage system, the parameters of buried pipes, collectors and other components are recommended to be reasonably determined by simulation to obtain the optimal heat storage effect.

Evacuated Tube Heat Pipe Solar Collectors Applied to Recirculation Loop in a Federal Building: SSA Philadelphia

Solar Energy ◽  
2004 ◽  
Author(s):  
Andy Walker ◽  
Fariborz Mahjouri ◽  
Robert Stiteler
Keyword(s):  
Solar Energy ◽  
Heat Pipe ◽  
Heat Loss ◽  
Heating System ◽  
Hot Water ◽  
Solar Array ◽  
Solar Collectors ◽  
Water Heating ◽  
Evacuated Tube ◽  
Recirculation Loop

This paper describes design, simulation, construction and measured initial performance of a solar water heating system (360 Evacuated Heat-Pipe Collector tubes, 54 m2 gross area, 36 m2 net absorber area) installed at the top of the hot water recirculation loop in the Social Security Mid-Atlantic Center in Philadelphia. Water returning to the hot water storage tank is heated by the solar array when solar energy is available. This new approach, as opposed to the more conventional approach of preheating incoming water, is made possible by the thermal diode effect of heat pipes and low heat loss from evacuated tube solar collectors. The simplicity of this approach and its low installation costs makes the deployment of solar energy in existing commercial buildings more attractive, especially where the roof is far removed from the water heating system, which is often in the basement. Initial observed performance of the system is reported. Hourly simulation estimates annual energy delivery of 111 GJ/year of solar heat and that the annual efficiency (based on the 54 m2 gross area) of the solar collectors is 41%, and that of the entire system including parasitic pump power, heat loss due to freeze protection, and heat loss from connecting piping is 34%. Annual average collector efficiency based on a net aperture area of 36 m2 is 61.5% according to the hourly simulation.

Experience With a Solar Heating ATES System for a University Building

1994 ◽  
Vol 116 (2) ◽  
pp. 88-93 ◽  
Author(s):  
E. Hahne ◽  
M. Hornberger
Keyword(s):  
Solar Energy ◽  
Heat Pump ◽  
Waste Heat ◽  
Heating System ◽  
Solar Heating ◽  
Coefficient Of Performance ◽  
Solar Collectors ◽  
Power Station ◽  
Heat Demand ◽  
Heat Store

At Stuttgart University, a solar heating system for an office building with laboratories and lecture rooms was installed in 1985. It consists of 211 m2 of unglazed solar collectors, a 1050 m3 water-flooded pebble bed heat store, and a heat pump. Heat can be supplied to the store from the solar collectors or from a power station (as waste heat). The whole system has worked successfully for five years under varied strategies. In the first two heating periods, the heating strategy was aimed to collect as much solar energy as possible. Thus, about 60 percent of the heat demand could be covered by solar energy; but the yearly heat pump coefficient of performance (COP) was only around 2.76. With an improved heat pump, a monthly COP of 3.6 was obtained. Heat losses from the storage amounted to about 20 percent.

scholarly journals Performance comparison of heat exchanger designs for a seasonal heat storage system

2016 ◽  
Vol 123 ◽  
pp. 1-7
Author(s):  
Tibor Horváth ◽  
Zoltán Pásztory ◽  
Kyle Horne
Keyword(s):  
Heat Exchanger ◽  
Heat Storage ◽  
Storage System ◽  
Performance Comparison ◽  
Seasonal Heat

Operation strategy of cross-season solar heat storage heating system in an alpine high-altitude area

2020 ◽  
Vol 29 (9) ◽  
pp. 1249-1259
Author(s):  
Haoran Li ◽  
Enshen Long ◽  
Yin Zhang ◽  
Hanyu Yang
Keyword(s):  
Solar Energy ◽  
Power Consumption ◽  
High Altitude ◽  
Heat Storage ◽  
Hybrid Control ◽  
Heating System ◽  
Control Mode ◽  
Operation Strategy ◽  
High Altitude Area ◽  
Installed Capacity

The full use of renewable energy sources such as solar energy to meet the various energy supply needs of buildings is now a research focus and an industry development trend, as energy consumption has been increasing and environmental pollution has become a serious problem. In the high-cold and high-altitude area in western China, due to the abundant solar energy and hydropower resources, the use of electric auxiliary cross-season solar heat storage heating system (CSHSHS) is an effective way to achieve clean heating. In this article, the authors applied a CSHSHS in a typical town in the Sichuan West Plateau and analysed and compared three operation strategies: heating storage priority control mode; electro-thermally assisted priority control mode and hybrid control mode. The results show that the heat storage priority control mode would require a large installed capacity of electrical auxiliary heat. The power consumption of the electro-thermally assisted priority control mode is high. The hybrid control mode can effectively reduce the installed capacity of the electrical auxiliary heat and the power consumption in the heating season. The solar fraction of the hybrid control mode was 38.29%, which has an obvious advantage. The results are of great engineering significance for optimizing the operation strategy of CSHSHS.

Experimental Investigation on a Latent Heat Thermal Storage Unit for Solar Cooling Application

Green ◽  
2011 ◽  
Vol 1 (2) ◽  
Author(s):  
L. Chidambaram ◽  
A. S. Ramana ◽  
G. Kamaraj ◽  
R. Velraj
Keyword(s):  
Solar Energy ◽  
Latent Heat ◽  
Solar Collector ◽  
Heat Storage ◽  
Storage System ◽  
Thermal Storage ◽  
Environmental Crisis ◽  
Storage Unit ◽  
Latent Heat Storage ◽  
Solar Cooling

AbstractConventional cooling technologies that utilize harmful refrigerants consume more energy and cause peak loads leading to negative environmental impacts. As the world grapples with the energy and environmental crisis, there is an urgent need to develop and promote environmentally benign sustainable cooling technologies. Solar cooling is one such promising technology, given the fact that solar energy is the cheapest and most widely available renewable energy that matches the cooling load requirements. However thermal storage systems are essential to overcome the disadvantage of the intermittent nature of solar energy and variations in the cooling demand. The enhanced utilization of solar energy and other consequences of thermal storage integrated systems have gained the attention of researchers in recent years. The concept of combined sensible and latent heat storage system is successfully introduced in several applications and it has many advantages. This paper presents the performance of the solar collector system and the charging characteristics of a PCM based latent heat thermal storage unit, which is designed to provide continuous supply of heat for the operation of 1 kW vapor absorption refrigeration unit. Investigations on PCM integrated thermal storage system have revealed improvement in heat storage capacity, lower heat loss and an increased solar collector efficiency due to better thermal stratification.

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