Workshop Background Information

Solar Cooling 2.0: A new generation is growing up

The workshop The New Generation Solar Cooling & Heating Systems held in Rome, Italy, on 23 September 2015 was the opportunity to check the status of solar cooling technology regarding both research and market developments. The workshop, which saw about 40 participants, was jointly organised by Task 53 of the IEA Solar Heating & Cooling Programme and the German Eastbavarian Institute for Technology Transfer, OTTI e.V. and took place a day before the 6th International Conference Solar Air-Conditioning of OTTI started. The half-day workshop was above all the stage for presenting the first outcomes of the international research cooperation TASK 53 under the title New Generation Solar Cooling & Heating Systems having started in March 2014, closing in 2017 and involving 10 active countries also from outside Europe.

The R&D road to competitiveness

According to the recent roadmap for solar heating and cooling, developed by the International Energy Agency (IEA) (link to http://www.solarthermalworld.org/content/global-roadmap-iea-calls-stakeholders-realise-vision), solar cooling should cover at least 17% of the total cooling needs by 2050. In the last ten years, however, the development has not been as fast and effective as it was expected to be. In only a few specific cases, is solar cooling economically competitive and has some market appeal. In the vast majority of potential applications, it is a solution which still has a too long payback time and therefore can be installed only in case of a very high incentive level as happens, for instance, in research and demo projects.

“Due to hydraulic complexity and high investment costs the first generation of solar cooling systems has shown not to be competitive,” Daniel Mugnier, Operating Agent of Task 53, made clear when opening the workshop in Rome. “Because of this situation, we cannot talk yet of a marketable technology but rather an intense R&D activity is still needed to develop a new generation of innovative systems towards Solar Cooling 2.0.”

Another relevant point discussed on the workshop was that the future trend of cooling and air-conditioning, has a chance to go more and more towards large-scale systems, as it is already happening for other applications of the energy sector. Such solutions, potentially including solar thermal energy for both cooling and heating, could also include small, medium and large district cooling grids. One additional feature of such plants should also be the parallel coexistence of different energy sources, both electrical and thermal, to supply energy for cooling use.

Although solar cooling is especially focusing on new buildings, the use of this technology in existing premises is not excluded, but requires some pre-requisites, such as the availability of sufficient roof space (an issue in modern cities with many high-rise buildings) and the capacity of the existing cooling distribution system to be adapted to the energy supply by solar.

Compact and easy to install Solar Cooling 2.0

How will such new generation of innovative systems look like? For sure, Solar Cooling 2.0 should be characterized by high compactness, easiness of installation, which means high compatibility for a direct coupling with chillers. Only with such a plug-and-play approach, solar cooling can be a valuable competitor of heat pumps, for instance.

One additional need is then to develop new standards and to have more monitoring data available since new potential customers want to know first of all how such systems are performing in real use. Another message coming from the workshop is ‘keep it simple’. A model example of such a philosophy is the relatively small (130 m2) solar plant in Banyuls, France, where the produced heat is used for air conditioning of the 4,500 m2 wine cellar: The system has been operating for about 25 years without major failures and mainly because of its simplicity.

The good news is that something is moving in the industry. In its presentation, Wei Zheng from the large, and well-known chiller manufacturer Yazaki from Japan announced that they are working on improving some of their chillers to make them more suitable for solar use. It is not anymore only solar going towards the cooling machine industry, but also the chiller producers trying to be compatible with solar! The main technical issue Yazaki is working on to allow their chillers to be activated at lower temperatures and with lower flow rates, thus increasing the efficiency of the solar field. An example shown by Yazaki reported about in increase of the solar fraction from less than 50% to 66% thanks to such improvements.

Photovoltaic as a partner or as a competitor?

A peculiarity of Task 53 is that it is dealing as well with solar PV cooling and then it is being run in collaboration with another IEA research programme, the Photovoltaic Power Systems (PVPS). Gaetan Masson, Operating Agent of PVPS Task 1, put it clearly: “For our business plans to work, with no more feed-in incentives available in the key countries, PV has to maximize self-consumption and cooling demand could fit to such a need. That is the main reason why compact units with PV modules directly coupled to a cooling machine are taking their position in the market at the moment.”

So, is PV a collaboration partner or a merciless competitor of solar thermal  in the struggle for potential customers? When explicitly asked about that, Mugnier explained his view: PV will be the main technology for small to medium scale single-user cooling application, for instance mono or multisplit systems, while, when going to large scale (industry, grids), solar thermal could be still the best option to go for.

More Information:

http://task53.iea-shc.org/
http://www.solaircon.com/
http://www.solaircon.com/workshop.html

The text was written by Riccardo Battisti, solar thermal consultant and market researcher working at Ambiente Italia in Rome, Italy.