The most important barriers for a broad application of small scale combined solar heating and cooling systems — further on called Solar Combi+ — and the solutions proposed by the project to overcome them are as follows:

1. Combined solar heating and cooling needs specialised design in order to make the single components play together optimally. So far every single system is designed from scratch. This (i) leads to a financial effort, which is not feasible for small applications, as design costs become prohibitively high in relation to hardware costs and (ii) often might overstrain the solar thermal installer, who would in most cases be the provider of the system to the end-user. Today there are no design guidelines for small scale systems and very few, yet not validated, package solutions on the market.

Virtual case studies will overcome this gap: Promising configurations will be identified, simulated for different typical conditions (i. e. utilization, climate, building type) and finally economically and ecologically rated. Out of the large number of virtual case studies, a small number of standard system configurations, which work best under different conditions are identified. Based on these, small scale sorption chiller and solar thermal industry will be able to provide consistent package solutions. These will enable planers and independent craftsmen to install reliable systems.

2. Small scale sorption chillers are expensive as production volumes are currently low.

The economical and ecological rating of the above described virtual case studies will allow identifying the most promising markets, where systems are yet at the edge of economical breakeven point or beyond, compared to traditional solutions. Accordingly tailored promotion and market strategies will considerably trigger the application of the technology. Following economies of scale will make small scale combined solar heating & cooling less expensive and thus viable in a broader range of applications and climates.

3. Small scale combined solar heating & cooling is not well known by traditional small scale solar thermal installers, planners, architects and potential clients.

Tailored dissemination plans include among other measures the training of solar thermal installers, targeted presentations to professionals, information of the public in most promising regions as well as advice to policy makers and promotion of pilot plant installation to public authorities.