Soil Source Heat Pump System Research Articles

Direct load control-based optimal scheduling strategy for demand response of air-conditioning systems in rural building complex

The abrupt surge in electricity consumption for air-conditioning (AC) in rural areas has exacerbated the rural power supply and demand imbalance, presenting a significant challenge to the reliability and stability of power provision in rural low-voltage grids. Implementing power demand response (DR) in buildings is recognized as an effective solution to address the grid's power imbalance and reliability issues. Among various building DR strategies, direct load control (DLC) stands out as a proficient approach to rapidly curtail building AC loads. However, applying this method solely to individual rural buildings proves less effective in peak regulation (PR). To fully exploit the DR potential of AC systems in rural building complex, it is essential to scale up the application of DLC. Consequently, a DLC-based DR optimal scheduling strategy is proposed for rural building complex AC systems. This strategy aims to meet PR demand and maximize the benefits for load aggregator. It establishes four DLC methods and differential compensation mechanisms, taking into account the varying thermal comfort requirements of AC users. The DR optimization model is solved using a genetic algorithm (GA), with PR demand derived from long and short-term memory neural network predictions. To validate the proposed strategy, a simulation study is conducted on a 200-unit farmhouse AC system, utilizing a typical rural soil source heat pump system in Xi'an, Shaanxi Province. The results demonstrate that the strategy surpasses the PR target by approximately 6.65 % during the DR period, while ensuring a minimum level of thermal comfort for all user categories. Additionally, it yields a PR benefit of 88.73 yuan per day for all users, thereby promoting the adoption of clean energy in rural areas.

Study on optimization of winter operation characteristics of solar-ground source heat pump in Shanghai

The operational characteristics of the combined solar-ground source heat pump system (referred to as SGSHPS) are influenced by local solar resources, climate characteristics, and operating modes. This paper aims to study the operational characteristics of SGSHPS in Shanghai under different operation modes, providing a reference for engineering applications of SGSHPS.Three operation modes were selected for this study: operation of the soil source heat pump, tandem operation mode 1, and tandem operation mode 2. The tandem operation mode 1 represents the heat pump source-side outlet fluid passing first through the buried pipe and then through the thermal storage tank, The tandem operation mode 2 represents the heat pump source-side outlet fluid passing first through the thermal storage tank and then through the buried pipe. The highest system COP was experimentally measured for tandem mode 1. TRNSYS software was used to construct the three oeration modes and obtain parameters such as unit COP, system COP, and buried pipe heat exchange.By comparing and analyzing the winter typical january month average system COP values obtained from experiments and simulations for each operation mode, The maximum error between the experimentally derived conclusions and the simulated conclusions is 9.9 %. The winter typical month january average system COP for the operation of the soil source heat pump was 3.26, while for tandem mode 1 it was 3.5, and for tandem mode 2 it was 3.44. Tandem mode 1 exhibited a 7 % higher system COP compared to the operation of the soil source heat pump, and a 1.7 % higher system COP compared to tandem mode 2. This indicates that the tandem operation of the solar-ground source heat pump is more energy-efficient than the operation of the soil source heat pump system. Therefore, tandem mode 1 is considered the optimal operating mode for SGSHPS in Shanghai during winter.

Optimal allocation method of multi-energy system based on hybrid optimization algorithm

With the rapid development of industry, the research of energy storage technology and renewable energy continues to be hot, and the energy industry opens the era of diversification. Multi-energy complementary has become a new trend in sustainable energy development, leading the energy industry to a new energy system of deep integration and integration of multiple energy sources. This paper proposes a hybrid optimization algorithm that combines particle swarm algorithms and Hooke–Jeeves​ (HJ) with a comprehensive evaluation index as the optimization objective, aiming to improve the speed of solving the capacity optimization of integrated energy systems. The multi-energy system configuration optimization platform that covers the index system, optimization model, and system analysis module was established to systematically solve the integrated energy system optimization configuration problem, moreover provide an important reference for integrated energy system design and implementation. Besides, the influence of optimization algorithms on the configuration results was analyzed. Taking the combination of soil source heat pump system and combined cooling, heating and power system as an example, this study quantifies and compares the optimization results and solution speeds of the hybrid algorithm and the traditional single optimization calculation. It is shown that the hybrid optimization algorithm reduces the amount of iteration steps by approximately 31% compared with the particle swarm algorithm and by approximately 48% compared with the HJ algorithm. This significantly improves the speed of the optimization computation while ensuring the accuracy of the computation results.

Fuzzy theory-based energy-saving control of solar thermal supplemental multi-energy heating system

In order to solve the problem of insufficient heating heat in solar thermal system and soil source heat pump system, and the problem of high energy consumption caused by traditional control mode in combined heating system, a multi-energy complementary solar thermal supplementary heating system controlled by fuzzy controller was proposed. The operating mode of the whole heating system was analyzed, and the relevant fuzzy model was established. TRNSYS and MATLAB simulation platform were used to simulate the system. The results show that the average performance coefficient of COPs(Coefficient of performance) is improved by 0.27 and the total energy consumption is reduced by 199.88kWh in 5 days compared with the traditional control system, which has the advantages of improving system performance and saving energy. At the same time, it is verified that the photothermal system can effectively maintain the long-term balance of soil temperature and make the heating system run efficiently for a long time.

Measurement and analysis of cooling (heat) performance of renewable energy technology projects based on ground source heat pump systems

The design, configuration and operation of the soil-source heat pump system in four actual projects are monitored, collected and investigated. Combined with various test parameters of the project, the energy efficiency of the ground source heat pump system was compared and measured, and detailed data analysis was conducted from the aspects of heat exchange of ground source heat pump system, heat efficiency coefficient of ground source heat pump system, performance of ground source heat pump unit and performance of soil source heat pump system. It provides a basis for the formulation of operation strategy of soil-source heat pump system in the future, so as to serve the sustainable development of energy saving technology of shallow soil-source heat pump system.

Analysis of Problems in Soil Source Heat Pump

The soil source heat pump system is characterized by high efficiency, energy saving, environmental protection, and full use of renewable energy. And today, when excessive energy consumption puts tremendous pressure on the environment, it has increasingly become the focus of attention. Most of the research aimed at it so far has focused on heat exchange, but there is almost no water balance problem. And many studies only draw some conclusions based on some theoretical calculations or numerical simulations. As a result, there have been many studies on the problem of heat transfer, and the research has deviated from the actual focus on theory and hydraulic balance. For the entire system, there is almost no comprehensive consideration of thermal balance, hydraulic balance, and economics. Therefore, this paper discusses the problems existing in the above three aspects of the soil source heat pump system, and then has some reference value for the actual project

Study on Temperature Field of Buried Heat Exchanger in a Residential District

The long-term stable operation of soil source heat pump system depends on the recovery characteristics of soil temperature field. Using DEST-h model of Hefei a high-rise residential buildings and FLUENT software to simulate software of soil source heat pump are analyzed through the summer and autumn season recovery after the change of soil temperature field around the buried pipe. It is pointed out that the intermittent operation of the compensation tower soil-coupled heat pump is beneficial to promote the recovery of soil temperature field. It has certain engineering application value for the improvement of soil source heat pump performance in hot summer and cold winter area.

Study of the ground water permeation s influence on energy pile heat exchange in porous medium soil

Energy pile heat storage technology is a typical soil source heat pump system, and features and parameters of soil have great influence on the heat storage of energy pile. Ground water permeation will take heat in soil away directly and if the permeation speed is too fast, the heat storage system of the energy pile even cannot store heat. In order to guarantee that the heat storage system of the energy pile can function well in practical working conditions, it is necessary to do further quantitative study of the ground water permeation’s influence on soil source heat pump. This study focuses on soil permeation’s influence on energy pile heat exchange through establishing the energy pile heat storage model and finds that when the permeation speed is less than 3×10-7m/s, it is the desirable heat storage condition; when the permeation speed is more than 1×10-6m/s, the energy pile heat storage system cannot store heat at all.

Performance study on heat and moisture transfer in soil heat charging

ABSTRACTIn some cold areas, the system performance of the soil source heat pump system is reduced by the decreasing underground soil temperature, which is caused by the thermal imbalance between the heating demand in winter and the cooling demand in summer. Soil heat charging with solar energy in non-heating seasons is proposed for solving the problem. It has been found from previous studies that the effect of the moisture transfer on the heat transfer within porous media could not be neglected especially under higher temperature difference. Therefore, this paper provides an investigation on the heat and moisture transfer in soil during soil heat charging at high temperature. A numerical model is developed for the study. The simulation results are compared with the testing data from the authors' previous study for the model verification. Based on the verified model, the performance of the heat and moisture transfer in soil during soil heat charging in a longer time and a larger area is investigated in the paper. The results show that the testing data match very well with the simulation results within a relative error of ±9% and the mathematical model is reliable for the performance prediction of heat and moisture transfer in soil heat charging. The soil volumetric water content (VWC) distribution tends to be stable after soil heat charging for 13 days and the heat source has an effective influence on soil VWC distribution within 2.4 m. The effect of the heat source temperature and initial VWC on the soil temperature and VWC distribution and heat power is proved to be obvious. Loam has a better performance in soil heat charging than sand.

Simulation and Analysis of Air-soil Dual Source Heat Pump Energy Consumption in Cold Regions

INTRODUCTIONThis paper mainly researches the practical engineering about Simulation of air-soil heat pump system in an office building of Shenyang, China. This system in the winter uses the air source as the main heat source and soil source as the auxiliary heat source for heating, in the summer only uses the soil source heat pump to refrigerate. METHODSThis paper mainly applies DEST software and TRNSYS software to study engineering air simulated analysis of soil heat pump system and compare with a single heat source. Analyzing the energy consumption of the dual heat sources pump system and its results were compared with the single soil source heat pump system to draw a conclusion. RESULTSAnalysis of energy consumption of dual-source heat pump system in summer and winter. And energy consumption analysis of single soil source heat pump system in summer and winter. CONCLUSIONSIn terms of energy consumption, the annual energy consumption of dual heat source heat pump system is 25962.23 kWh. The annual energy consumption of single soil source heat pump system is 45573.78 kWh, saving about 43.03% of energy consumption. The superiority and development prospects of the dual heat source heat pump system is obvious and promising, in the operating cost and conservation area. This project was financially supported by the National science and technology support plan sub-topic (2011BAJ05B01-04).

Experimental study on heat and moisture transfer in soil during soil heat charging for solar-soil source heat pump compound system

Due to the imbalance of heating and cooling demand, the soil temperature decreases after several years' operation for soil source heat pump system, and consequently the coefficient of performance (COP) decreases. Soil heat charging with solar energy was proposed for solar-soil source heat pump compound system. Many studies have been carried out to investigate the heat and moisture transfer in soil for soil heat charging, but they failed to provide a clear description and explanation of the coupled and mutual effect between heat and moisture transfer. This paper presents an experimental study on the heat and moisture transfer in soil heat charging. The simplified testing rig was constructed to investigate the coupled and mutual effect of one-dimension horizontal heat and moisture transfer in soil heat charging. The results show that, peak volumetric water content (VWC) occurs firstly at the position near heat source and moves towards the other cold end of the tested soil pillar, but it is limited in an area near heat source. The time consumption and value for peak VWC increase with the increasing heat source temperature at the same initial VWC and increase with the increasing initial VWC at the same heat source temperature as well. The heat source temperature is a main factor affecting the peak soil temperature and peak VWC, while the initial VWC has little impact on them.

Discussion of Ground Source Heat Pump System Heat Balance in Severe Cold Area

This template comprehensive analysis of the causes of soil heat balance, heat balance of soil caused by the results, heat balance of soil factors influence, several domestic thermal imbalance of soil heat balance and common measures to solve the problem, for the future of the soil source heat pump system design for the constructive suggestion.

The Matching Research of Soil Source Heat Pump and Central Heating System in Cold Region

Using Dest software simulation benchmark building the dynamic heat load, analyzing its distribution pattern, at the same timewe can also get heat pump units in the COP value is different under different working condition, then the soil source heat pump and central heating complementary heating system, undertake in soil source heat pump system design heat load, under theconditions of different proportion of the whole system operation energy consumption, initial investment analysis, we conclude thatthe soil source heat pump and central heating complementary heating systems of different energy matching optimization features,this provides a reference for practical engineering.

Applicability of Ground Source Heat Pump in Cold Areas

The essay introduces principles, forms and characteristics of the soil source heat pump system, explores applicability problems of the soil source heat pump system in cold areas, raises several ways to improve technology problems in the actual running of the soil source heat pump, briefly analyzes from the economic perspective in an combination of relevant materials, and points out that the soil source heat pump has certain applicability in cold areas.

Study on Operating Characteristics of Soil Source Heat Pump System of a Residential District in Summer

Load characteristics of the residential district is different from public buildings, so residential district of soil source heat pump air conditioner system operating characteristics are different from public buildings. Studies have been made on operating characteristics of soil source heat pump air conditioner system in a residential district in Qingdao, analyzing energy consumption of soil source heat pump air conditioner system and exploring its operation laws. It provides the basis for design, operation and control strategies of soil source heat pump system.