This project has financed Danish participation in the IEA SHC cooperation on solar cooling. The Danish contribution is a calculation model for the AC-Sun system, which uses new and revolutionary thermo-cooling technology, and AC Sun has had prototypes of the system developed and measured. The work is continuing in and EDDP-funded project (ESA-64009-0223). Absorption chillers at Skive City Hall have also been measured, and system development, modelling, analyses and measurements of adiabatic.cooling systems and cooling towers have been conducted. At the completion of the task, solar cooling was still considered and uncompetitive technology.
Project description
The use of air-conditioning in Denmark is strongly increasing. Most new office buildings are equipped with air-conditioning plants. Furthermore the new building regulations means an increasing need for cooling solutions not making use of electricity. Solar cooling is an energy efficient way to cool buildings, which is also applicable in Denmark, since there is a big agreement between solar radiation and the need for cooling. The IEA SHC Task 38 has the following activities. 1) Development and test of solar driven air-conditioning system for dwellings and stores etc. 2) Development of concepts for small or medium sized systems as well as development of optimized and standardized systems for individual uses. 3) Documentation of new pilot and demonstration projects as well as evaluation and performance procedures. 4) Collection and elaboration of documents on design, installation, utilization. 5) Analyses on new concepts and technologies with focus on thermodynamic studies and literature. 6) Comparison and evolution of simulation tools with respect to design and system analyses. 6) Other activities such as news-letters, workshops, education material and 2. edition of Handbook for Solar Cooling for Planners
Results
IEA SHC Task 38 Solar Air-Conditioning and Refrigeration ran from October 2006 to December 2010. Denmark was represented in the task from January 2007 to December 2010. The aim of the task was to encourage use of solar powered refrigeration and air conditioning systems in particular at residential, commercial and industrial sectors. Furthermore, the aim was to contribute to new research and development activities on new systems and concepts. Because the use of air-conditioning in Denmark is increasing rapidly, it has been important with Danish participation in the task. Most new Danish office buildings already make use of air conditioning. In addi-tion, the new energy provisions in the building regulations increase the need for cooling solutions that do not use electricity. An increased frequency of hot summers caused by climate change will also help to in-crease the need for air conditioning in homes. The main findings of the task are given in the new handbook that will be published in summer 2011. The Danish project group has provided input to the international reports of the task. PlanEnergi was involved in analysis of measurements of the absorption system of 105 kW established year 2007 in Skive City Hall. In cooperation with the Technological Institute is also from the analyses developed and tested an alternative method of regulation (see below) and delivered measurement data for use in task. The Technological Institute has participated closely in preparing the report for subtask A Small Systems. Furthermore The Technological Institute had the role as coordinator of activities around the optimization of heat rejection. In this context it is especially the derived electricity for pumps and fans in the heat emitter (cooling tower, dry cooler, etc.) that are looked at. Traditionally heat driven refrigeration machines are con-trolled by regulating the driving heat flow (lower regeneration temperature). This has however, for most types of systems, negative impact on the system efficiency and thus the power consumption of auxiliary equipment. This has led to the development of an alternative regulation strategy tested at Skive City Hall plant. In 2009 it was planned to attach adiabatic pre-cooling of the air cooling coils at Skive city hall, however the solution proved to be quite expensive. Further optimization of the solution was therefore not imple-mented, because detailed analysis of operational data of the system showed great potential in the introduc-tion of the before mentioned regulation strategy. Instead Plan Energy conducted further optimization of the plant, and measurement data implemented in the spring of 2010 and preliminary data show much smoother operation and significantly less power consumption. The study of adiabatic pre-cooling was instead made in a laboratory setting at the Technological Institute. This was combined with the test of a new air cooling system, based on indirect evaporation of water. The test was conducted on a cooler purchased from the Netherlands and a MST project was demonstrating this technology to heat driven air conditioning in a supermarket. As a derivative a PSO project on the development of small efficient cooling towers was started at the Tech-nological Institute in early 2009 and measurements was performed at the first prototype. The presentation was shown on the meeting in Aarhus, April 2010. Part of the Danish team has also been the company AC Sun which in the period has worked with develop-ing a new and revolutionary thermo-cooling technology. AC Sun has designed and produced an optimized prototype 2 and begun data collection. Prototype (2) is flexibly designed for testing different bearing solu-tions. The prototype is installed in a buffer tank connected to the heating elements as external heat source acting as a collector. Prototype 2 will be used as the final internal testing station before the final design and manufacture of test facilities for field test in 5 test stations respectively Denmark, Germany, Italy, Spain and Malaysia. Most of the testing stations are expected operating in spring 2011. Ellehauge & Kildemoes during the period conducted the project management and worked with the calcula-tion and evaluation of the AC-Sun System. A TRNSYS model for simulation of the system has been built
