In May 2008 the worldwide first installation of a chillii® Cooling Kit 8 for a two family house in Alzenau, Germany based on a chillii® STC8 (Fig. 5.) was successfully put into operation. The necessary heat for driving the machine is provided by 24 m2 flat collectors and a biomass back-up. As a buffer 2.000 litre hot water storage is used. An electrically high efficient dry re-cooler with water spraying is used for an effective re-cooling of the 22 kW waste heat of the adsorption chiller. The cold distribution is effected by fan coils.

The chillii® Cooling Kit 8 is until now besides others installed in residential or office buildings in the following countries: Germany, Austria, Italy and China.

For the new training centre and office building of Bachler Austria, Austria a complete solar cooling system with biomass back-up has been installed between winter 2006 and spring 2007. The chiller that is used is a chillii® PSC10 (Fig.6.) for a required cooling load of 9 kW and as recooler a 26 kW wet cooling tower as well as in addition a swimming pool. The wet cooling tower is operated with very low re-cooling temperatures of 24/29°C for the Middle-European application. The requested solar heat is delivered by 40 m2 flat plate collectors, which are mounted at the faqade and on the ground and is stored in three hot water storages with 1.5 m3 each. The cold distribution is done by concrete core activation (cooled ceilings) with cold water temperatures of 16/19°C and a dew point thimble for cooling of the training and office rooms.

Further chillii® PSC10 absorption chillers are installed in different thermally driven systems worldwide, e. g. three in Germany, one in Canada and two in Malta. The current chillii® PSC12 is installed for the first time together with a chillii® Solar Cooling Kit 12 in Italy. A second chiller is now running in Spain.

With the chillii® WFC18 water/lithium bromide absorption chiller four chillii® Cooling Kits 18 for air-conditioning applications have been realized until now, one in Germany (bakery), one in Syria (residential building), one in Romania (university) and one in Australia (office building).

3. Conclusion

The energy demand for air-conditioning is rising rapidly in Europe and worldwide. Thermal cooling with solar thermal heat, district heat, process waste heat, CHP waste heat or biomass can reduce the energy consumption and the CO2 emissions considerably. But if a backup system is used, which is not based on renewable energy sources; the primary energy consumption rises again. Basically the solar fraction of solar cooling kits should be higher than 70% or an existent complete solar heating system would even be better. In the small-scale capacity range with up to 30 kW several water/lithium bromide absorption chillers; one ammonia/water absorbers as well as two water/silica gel adsorption chillers are recently available on the European market. For an economical operation of solar cooling systems the additional investment costs for the sorption chillers have to be further reduced, which is absolutely expected at higher sales numbers. At very low heat prices, for example at existing solar thermal plant for the heating support, thermal solar cooling systems can nearly compete today with common electrical compressor chillers. Because of the general trend in Europe to larger solar thermal plants for the heating support, small-scale sorption chillers offer good opportunities to use efficiently the summery heat.

References

[1] 71 Mio. Klimagerate — neuer Weltrekord, cci, 9 (2007) 30.

[2] U. Jakob, Overview on Small Capacity Systems, Proceedings of the International Seminar Solar Air­Conditioning (2008) Munich, Germany, 73-80.

[3] U. Jakob, Auch die Sonne kann kuhlen — Ein Uberblick uber Sorptionskaltemaschinen kleiner Leistung, Erneuerbare Energien, Vol. 18, 6 (2008) 64-70.