Seasonal Solar Thermal Storage Research Articles

Dynamic characteristics and energy efficiency evaluation of a novel solar seasonal thermal storage - heating system

This paper proposes solar seasonal thermal energy storage system compounded with long-term and short-term energy storage tanks for a single-family dwelling, which using assisted water source heat pump to further improve the systems stability. With the objective of improving the solar energy utilization efficiency and reducing the primary energy consumption, the dynamic simulation model of the “heat collection-heat storage-heat supply” system under the non-stationary boundary conditions throughout the year is established. The energy transfer and conversion law of each subsystem and the dynamic operation characteristics are analyzed through simulation method. The system cooperative control strategy is proposed and parameter optimization is carried out. Results indicate that the annual heat collection efficiency of the water source heat pump composite system has been improved by 2.2 % compared with the electric auxiliary heating system. Meanwhile, the heat storage efficiency and the solar energy guarantee rate increased by 5.8 % and 8.3 %, respectively. Moreover, the optimal water source heat pump composite system not only improves energy efficiency and achieves the cost savings compared with the electric auxiliary heating system, but also reduces carbon dioxide emission by 10.3 %, which have great advantages for energy saving and emission reduction.

Study on heat transfer process of insulated floating cover of water pit for solar seasonal thermal storage

Water pit thermal energy storage (PTES) can transfer the solar energy heating from the non-heating season to the heating season, which can efficaciously cope with the mismatch problems in energy intensity, usage time and space of solar energy heating system. The long-term PTES system is stable and efficient, avoiding the idleness and waste of the collector field. The insulating floating cover is the most expensive part of PTES and it is also the key factor to determine whether the thermal stratification of the PTES can be formed. This project studied the heat transfer process of insulated floating cover with a finite element model of a 500 m3 water pit in Yanqing, China, and the result is validated by experimental data. The difference between the numerical simulation consequences and the experimental consequences is about 5.6%, and the comprehensive heat transfer coefficient of the insulated floating cover can reach 0.186 W/(m2 K). The verified numerical model can intuitively display the temperature distribution and other key parameters of the insulating floating cover, which provides an important reference for the design and manufacture of the insulated floating cover.

Analysis of solar seasonal storage in rural residences with Zhongyuan region as an example

A combined system of refrigeration and heating unit with seasonal solar thermal storage was presented in this paper. Based on the climate character of the Zhongyuan region, China, the system?s performance in rural residences was studied. A computational program was established based on the DEST software, the solar heat collecting capacity, heat collecting efficiency, and other parameters were analyzed. The results showed that the system can supply 76.28% heating load and 40.14% cooling load, when the total collector surface area equals to 40 m2 and heat collecting temperature is 80?C. The results will provide theoretical support for the system?s optimization.

Basic Research of Solar Seasonal Thermal Storage Capacity Increase to Existing Heating System

Based on the principle of deepening the use of solar which is renewable energy, we proposed a new system that utilize solar seasonal thermal storage capacity to increase existing district heating, the peak load will be met by solar seasonal thermal storage is the salient feature of this system. This article described related content of the system basic research, including system design and operation control mode, also discussed the physical model of the major part of the composition system, to lay the foundation for in-depth study.

Experimental study of a solar-assisted ground-coupled heat pump system with solar seasonal thermal storage in severe cold areas

This paper presents the experimental study of a solar-assisted ground-coupled heat pump system (SAGCHPS) with solar seasonal thermal storage installed in a detached house in Harbin. The solar seasonal thermal storage was conducted throughout the non-heating seasons. In summer, the soil was used as the heat sink to cool the building directly. In winter, the solar energy was used as a priority, and the building was heated by a ground-coupled heat pump (GCHP) and solar collectors alternately. The results show that the system can meet the heating–cooling energy needs of the building. In the heating mode, the heat directly supplied by solar collectors accounted for 49.7% of the total heating output, and the average coefficient of performance (COP) of the heat pump and the system were 4.29 and 6.55, respectively. In the cooling mode, the COP of the system reached 21.35, as the heat pump was not necessary to be started. After a year of operation, the heat extracted from the soil by the heat pump accounted for 75.5% of the heat stored by solar seasonal thermal storage. The excess heat raised the soil temperature to a higher level, which was favorable for increasing the COP of the heat pump.