This type of systems as been on the market for about a decade. However, they are mainly employed in single-family houses in Central and Northern Europe (Weiss, W. (deed. ): Solar Heating Systems for Houses – A Design Handbook for Solar Committees, James & James Ltd. , London, 2003). Their market share in the single-family house sector is still increasing. In larger applications, e. G. Multi-family houses, most solar thermal systems supply only domestic hot water. A few multi-family house applications have been realized but they cover quite low solar fractions in the order of magnitude of 10 %.
One reason for this is that larger collector areas that are necessary for higher solar fractions, cause problems during stagnation in summer. This problem is even more prominent in southern European countries with a short heating season where the market share of solar committees is still very low. The proposed project will solve this problem by using the surplus energy for cooling. On the other hand, cooling of residential buildings in Southern Europe and of commercial and industrial buildings all over Europe is an increasing and promising market.
Approximately 100 solar cooling systems eve been installed worldwide so far. Most of them are quite large systems with a cooling power above 100 k. However, as reported by experts in the Solaria Heating and Cooling Programmers Task 25 (Hans-Martin Henning (deed. ): Solar- Assisted Air-conditioning in Buildings – A Handbook for Planners, Springer- Average, Wine, New York, 2004) more knowledge and experience is needed. There is limited simulation and monitoring data and practical design know-how for system optimization available.
In addition, very few combined solar heating and cooling applications have been realized and the solar fractions are generally to very high. Therefore, a combination of solar heating and cooling systems is an ideal solution that has the potential to lead to both high solar fractions and economical systems due to double usage of the collector field and other system components. Such systems can make a significant contribution to the energy supply in Europe, as described in the White Paper “Energy for the Future: Renewable Sources of Energy”.
ENEMA (IT), CASANOVA (IT), FINCH (IT), DEEMED (FRR), MIMIC IT (DC), Del (DC), CRESS (GAR), BEEBE(GAR), GAPER (GAR), SEC(B), ZERO (CNN), CABLE (CNN) A Short Description of the Technology: The solar demo plant will most probably be built in a residential area (still to be identified) and will provide heat (and cooling) to residential apartments with a total living area of about 700 mm. The latter is a typical size of a multifamily building, which represents a significant share of the residential buildings in Greece and therefore offers a high replication potential.
In the figure below a schematic representation of the plant and its operation mode during summer are given. The apartments are ownership of the Greek Workers’ Housing Organization. The main system components are the solar thermal collectors (selective flat plate), the irradiative heating and cooling elements (internal to the walls), the absorption or adsorption-cooling machine and the storage. The cooling machine receives thermal energy (Q) at high temperature (i. E. , 70-ICC) from the collectors’ field and provides the useful cooling (ICQ) services to the building.
As in every heat driven system, the sum of the heat provided for operating the chiller at “high” temperature and of the heat extracted from the building (at low temperature), namely (Q+ICQ), has to be rejected at a mid imperative level. Often the external ambient is used as heat sink for the heat rejection (e. G. , through a cooling tower). In this HIGH-COMBO system, Q+ICQ will be delivered to the boreholes (that are positioned around the water storage tank). Consequently, the earth Source: GIBBS surrounding the storage will be heated, thus reducing the losses of the water storage tank.
When, during summer, there is solar energy available but no need for cooling or domestic hot water, the produced heat will be delivered into the water tank storage. The storage will be heated up to about ICC in summer. The combination of a good insulation (yellow area in the figure), an additional low cost insulation (light blue area) and the surrounding earth heated by the boreholes will maintain the storage high temperatures, so that it will cover a substantial amount of the heating load during winter. Source: EIA Task Obviously, a part of the heating load will be covered directly by the solar gains during winter.
Project partners: ABA/adsorption cooling The project aims at promoting and widespread disseminating EX. innovative Research and Technology Development and Demonstration results, as well s echo-sustainability criteria in building sector, which include: energy efficient building materials, components and systems not yet introduced into the building market or in their first market phase; innovative applications of heating/cooling and power supply technologies, combined with the use of renewable energy sources, in building sector; best EH demonstration echo-building projects.
Q ICQ Q +ICQ Water Boreholes Mild temperature heating/cooling element Follow some basic information on the system sizing and cost of the Greek and the other demo plants: Collectors area: about 150 m flat plate collectors 3 3 Type and size of storage: Seasonal storage – Volume: about 400 m (tank only will be about 250 m surrounded by boreholes; their exact number and depth will be specified during optimization). Indicative data for the storage are following: Water storage: buried, cylindrical, either concrete or steel with a radius of about 3. Meters and height of about 7 meters. Boreholes: U-shape plastic tubes, surrounded by concrete, about 8 meters in depth, with a distance among them in the order of 1 meter. The boreholes number will be in the order of a few tenths. Cooling heat driven machine power: 70 k (absorption or adsorption). Estimated solar fraction: 80% of total load (i. E. , sum of DHOW, space heating and cooling load) Budget: 190 k?, including the monitoring equipment. 2 Results and Achievements: Preliminary calculations have shown a sound economy of High-Combo plants.
In particular, the range of simple payback time for typical High-Combo systems, in the near future, is estimated to be between 7 and 13 years (depending on the climate conditions, the load and the plant configurations), while their lifetime is over 20 years. In case of Coos agreements, the AIR (Internal Rate of Return), from the Coco’s side, can often be higher than 8%. It is worth mentioning that the above estimations are “on the safe side” as they do not take into account any of the following possible advantages: Possible increases (over the inflation rate) of conventional fuels and electricity prices. Subsidies for High-Combo plants. The cost reduction that will occur when High-Combo systems will have a substantial penetration into the market. The added value for the houses (or buildings in general) where High-Combo systems are installed. With the above considerations, it is obvious that the High-Combo systems could be promising option for the European and worldwide heating and cooling market. An estimation of the payback time for the Greek High-Combo plant is following.
Different from common market promotion approaches, where market operators are only simple message receivers, the project proposes an innovative approach: Echo-Building Club is a virtual round table, around which building market operators will be main actors for market penetration of research and demonstration results, through the following actions: determining what are ore appropriated innovative RED results for local market transferring; demonstrating the feasibility of the research and demonstration results on real cases.
Main data (almost all data are specific, i. E. Per mm of collector area): 2 Solar yield: 800 skew/m Energy provided to space heating and domestic hot water: approximately khaki/m Energy provided to the solar cooling machine: approximately khaki/mm Cost of the solar plant (without the extra monitoring equipment): 800 ?/m 2 2 Clarifications for the cost: the total budget for the plant to be constructed is 90 k? from which the monitoring equipment will cost approximately 40 k?.
Therefore, the cost for the plant without monitoring is approximately 1 50 k? 2 which corresponds to 1000 ?/m . However, it is clear that this price is particularly high since the plant is a prototype 2 with a lot of innovations. It is expected that even in the first market steps, the price will not be higher than 800 ?/m , with many possibilities for further reduction. According to the above, the conventional energy savings are as follows: The savings in thermal skew are about 500 skew/m f we consider the boiler efficiency approximately equal to 80 %.
This corresponds to 50 litter of oil or to approximately 35? (always per mm of collector area) by assuming an oil price of 0,7?/1. On the other hand, assuming a Cop (coefficient of performance) of the cooling machine equal to 0,9, the cooling 2 energy delivered to the load will be 360 cooling skew/m . If we assume that this corresponds to half electric skew of 2 savings and a price for electricity of 0, 165 ?/skew, the resulting savings are about 30 ? (always considered per m of collector area). Thus the total savings are 65? per m of collector and year.