The Prospects Of The Combination Of PVT With Air Source Heat Pumps And Ground Source Heat Pumps

Introduction

Under the impetus of the global carbon neutrality strategy, the energy systems of buildings and industries are rapidly moving towards cleanliness and efficiency. Photovoltaic and solar thermal integration (PVT), air source heat pump (ASHP), and ground source heat pump (GSHP) have gradually become typical representative technologies among them. The PVT system has both power generation and heating functions, while various types of heat pumps can efficiently obtain environmental heat from air or ground sources for heating and cooling. If PVT is organically combined with air source heat pumps and ground source heat pumps, it is possible to achieve a comprehensive energy solution integrating electricity, heat and cold, providing a new direction for building energy conservation and the development of distributed energy.

I. A Brief Description of the Working Principles of PVT and Heat Pump Systems

1. PVT system

PVT is a system that integrates photovoltaic and solar thermal energy. The photovoltaic part converts radiant energy into electrical energy through solar cells. The solar thermal section collects the residual heat of the photovoltaic panels through the back sheet or pipelines for heating water or air. PVT not only enhances the power generation efficiency of photovoltaic modules but also provides additional thermal energy.

2. Air Source Heat Pump (ASHP

ASHP transfers low-grade heat from the air to water or air through components such as compressors, evaporators and condensers for heating or cooling. Its coefficient of performance (COP) is usually between 2.5 and 4.5, meaning that for every unit of electrical energy consumed, 2.5 to 4.5 units of thermal energy can be obtained.

3. Ground Source Heat Pump (GSHP

GSHP takes advantage of the relatively stable temperature of underground soil or water bodies to conduct heat and cold exchange. Compared with ASHP, GSHP is less affected by ambient temperature and has more stable energy efficiency, but its installation cost is higher.

Ii. The Logic of the Combination of PVT and Heat Pumps

The combination of PVT and heat pumps is not a simple superposition but a complementary relationship:

PVT provides electrical energy

The operation of heat pumps requires electricity. The electricity generated by PVT can directly drive the heat pump, thereby reducing the reliance on the power grid.

PVT provides a low-temperature heat source

The efficiency of a heat pump is closely related to the temperature of the heat source. If the waste heat from the PVT backplate can be used as an auxiliary heat source for the evaporator, it will enhance the working efficiency of the heat pump, especially in cold seasons.

The heat pump operates stably

The heat pump can continue to operate at night or on cloudy days, compensating for the energy fluctuations caused by insufficient solar radiation in the PVT.

Combined cooling and heating supply

Through the combined system of PVT and heat pump, a comprehensive supply of electricity, hot water, heating and cooling can be achieved, meeting the diverse energy demands of modern buildings.

Iii. The Prospects of the Combination of PVT and Air Source Heat Pumps

Solve the problem of declining efficiency in winter

Under low-temperature conditions in winter, the evaporator of ASHP is prone to frosting, and its efficiency drops significantly. If the heat provided by the PVT during the day can preheat the evaporator, it can effectively reduce the frequency of frosting and improve operational efficiency.

Suitable for urban architecture

Urban buildings generally have limited roof areas and high energy demands. The PVT+ASHP system can be installed on the roof, generating electricity, providing heat and offering domestic hot water. It is a space-friendly solution.

Economic analysis

Initial investment: Relatively high, but lower than that of ground source heat pumps.

Operating cost: Reduce the cost of purchasing electricity through PVT self-generation.

Payback period: It is usually 7 to 10 years in regions with high energy prices.

Application Case

In Italy, Spain and other places, some hotels have adopted PVT-driven ASHP systems, which can achieve self-sufficiency in green energy for both summer cooling and winter heating.

Iv. The Prospects of the Combination of PVT and Ground Source Heat Pumps

Improve the efficiency of ground source heat pumps

GSHP consumes electrical energy. If it is powered by PVT, the operating cost can be significantly reduced.

The waste heat from PVT is used as an auxiliary heat source

In winter, the underground temperature is stable but still relatively low. If the waste heat generated by PVT can be transferred to the underground through heat exchange pipes, it can improve the operating conditions of the evaporator of the ground source heat pump and increase the overall COP.

Long-term operational reliability

GSHP has a long service life and stable operation. When combined with PVT, it can form an efficient, low-carbon and long-life system, especially suitable for long-term operating public buildings such as schools, hospitals and industrial parks.

Economic analysis

Initial investment: Higher than ASHP, mainly due to the high costs of drilling and pipe laying.

Operating cost: The lowest, due to the stable underground temperature and high energy efficiency ratio.

Payback period: Usually 8 to 12 years, but the lifespan can reach over 20 years.

Application scenarios

The combination of PVT and GSHP is more suitable in cold regions such as Northern Europe and Germany, which can meet the heating and domestic hot water demands throughout the year.

V. Technical and Application Challenges

High initial cost

Whether it is ASHP or GSHP, the system complexity increases when combined with PVT, and the investment threshold remains relatively high.

System matching problem

The output characteristics of PVT power generation and heating do not fully match the demands of heat pumps, and intelligent control and energy storage are required in coordination.

Insufficient standards and promotion

At present, there is a lack of unified standards for PVT+ heat pumps, and the experience in engineering design and construction is limited.

Low user awareness

The market has a certain understanding of PVT and heat pump individual technologies, but it is still unfamiliar with the combined composite system of the two, and demonstration projects are needed for promotion.

Vi. Future Development Directions

Intelligent control system

Through artificial intelligence and the Internet of Things, real-time matching between PVT output and heat pump load is achieved to optimize operation strategies.

Combined with energy storage technology

Electric energy storage: Stores electricity during the day and drives heat pumps at night.

Thermal energy storage: The waste heat generated by PVT is stored in the water tank or phase change materials to balance the day-night fluctuations.

Modular design

In the future, PVT and heat pumps may launch integrated products to reduce the difficulty of system integration.

Policy promotion

Under the background of carbon neutrality policies, the government is expected to offer subsidies or green building credits to promote their application in public institutions and commercial buildings.

Vii. Conclusion

The combination of PVT with air source heat pumps and ground source heat pumps not only enables diversified complementarity of energy forms but also significantly enhances energy utilization efficiency and reduces building operating costs. From commercial buildings, public institutions to industrial parks, this kind of composite energy system has broad application prospects. Although it still faces challenges such as cost, standards and market recognition at present, with technological progress and policy support, the PVT+ heat pump system is expected to become an important part of the green building energy system in the next decade.