04 jul Solarus blog: PVT (Photovoltaic-thermal) panels for sustainable heat generation
The concept of PVT (Photovoltaic-Thermal) hybrid panels is not new. However, it has gained significant importance in last few years leading to publication of market data for the first time in Solar Heat WorldWide 2019 edition from International Energy Agency (IEA). As per the report, 1.1 million m2 area has been covered by PVT collectors by end of 2018 across the globe. 90 % of this installed area is in France, South Korea, China, Germany and Israel in respective order. While most of the world has seen growth in water PVTs systems, France is an exception with majority market share by air PVTs. Meanwhile PowerCollector from Solarus has gained recognition across continents, in western Europe, India and South Africa.
Why are PVTs growing?
The continuous drop in prices of photovoltaics (PVs) in combination with supporting legislations (such as grid import, subsidies, etc.) across globe made it possible for PV to spread to private customers, especially residential customers. In addition, there is high demand for hot water for sanitary purposes as well as space heating. Story is similar in hospitality buildings such as hotels, hospitals, etc. Many industries also require electricity and hot water in processes. This created opportunities for a product that can provide both electricity and hot water. Therefore, PVTs that can produce both heat and electricity makes best case for the limited roof space. As the market share of these grew, governments took notice of them and they gained recognition in relevant legislations. Currently, most countries have supporting subsidies or framework that is further boosting the sales of PVTs. Currently it is possible for PVTs to achieve Solar Keymark and SRCC label which was originally meant for solar thermal only products.
Are PVTs answer to sustainable heating?
Primarily there are two types of PVTs – Air PVTs and water PVTs. Air PVTs pre-heat the air which can be used in ventilation systems and also in heating of space. This requires the building to have a centralised air heating system which are common in commercial as well as hospitality buildings. Such PVTs can also be used in some drying processes especially in agriculture and processing industries. However, these PVTs are not suitable for any kind of water heating.
Water PVTs can be further divided into two types – low temperature PVTs and high temperature PVTs. Low temperature PVTs set themselves as a next generation PV because they produce very low temperature heat which has found use in being used as a source for heat pump. These PVTs compensate for electricity consumed by heat pumps and at the same time marginally improve the performance of the heat pump. These PVTs exist only because of heat pump and find no use in places where heat pumps are not used.
Finally, high temperature PVTs set themselves up as the next generation of solar thermal because their main function is to supply heat directly to the application which producing electricity at the same type. Solarus PowerCollector is an example of this type. These kind of PVTs are more flexible to be used in any kind of building. They can be coupled with heat pumps as well as conventional boilers. In warmer climate they can even work autonomously without requiring any other source of heat. Therefore, these PVTs have the highest CO2 reduction potential among all PVT technologies. They also offer the highest reduction in energy bills of consumers. They outperform the other types of PVTs in the applications requiring hot water, such as sanitary hot water in households, hotels and hospitals, etc., and industrial processes.
Therefore, to answer the question, whether PVTs are optimal solutions for sustainable heating?, PVT companies have identified that each consumer needs both heat and electricity. In short span of time they have been able to make a mark in the solar energy market. Each type has found its niche market depending on the local building design and existing energy delivery infrastructure. In time they will gain more and more prominence as the awareness towards this technology garnered interest among legislators and general public.
Is there a future of PVTs?
There are new markets opening up for PVT in addition to already established European market. India, China and Mexico are leading the way in solar thermal installations. With the increase in life standard sanitary hot water has become more important than ever. New legislations are coming up which put limits on use of fossil fuels. In addition, real estate developers and hotels want to claim green brand to distinguish themselves from others. Solarus has established itself as a hot water PVT collector and has seen a steady growth and traction in hospitality sector in South Africa and India. At the same time PowerCollector is becoming popular in food processing and water treatment in Netherlands. No PVT market growth data has been reported, however the fact that IEA recognizes PVT as an independent category, combined with the fact that there are 26 PVT manufacturers in 11 countries which have published information.
PVTs are the most suitable in the following cases:
- Both heat and electricity demand
- Limited roof-space
- High renewable energy generation/high CO2 emission reductions
- Pre-heating applications
- 100% renewable energy solutions for limited roof-space
Solarus has more than 40+ installations for (pre-)heating and hot water applications in hospitality, residential and industrial sectors. Our installations include DHW, WKO charging, pre-heating applications. Our prominent installations are Henri Willing Cheese factory and Waterbedrijf (Sports park and Kolenpark) in the Netherlands and Vineyard, The Marriott (15 on Orange), Park inn, Hilton hotels in South Africa among others.