A number of activities in different fields were carried out: SIMULATION PROGRAMMES:-A state of the art of solar energy programmes developed and used by Solar Energy Center Denmark was worked out.-Simulation programmes for solar domestic hot water systems were built out so that a flexible variable hot water consumption could be simulated. The programmes were further developed so that the mixing occuring in the solar tank during hot water tapping could be simulated.-A plan for future activities on simulation programmes for Solar Energy Center Denmark was worked out. TEST METHODS:-Existing test methods for solar tanks were evaluated. Based on this improved test methods for the future were worked out.-Investigations on mixing in solar tanks during hot water tapping were carried out.-Existing test methods for evacuated tubular solar collectors were evaluated. Based on this recommendations for future testing of evacuated tubular solar collectors were worked out.-Existing simulation programmes were evaluated by means of measurements for different solar domestic hot water systems in a test facility. ASSISTANCE FOR THE SOLAR ENERGY BRANCH:-Investigations of a solar heating system based on the natural gas burner/solar tank-unit Block Gas Sol was carried out.The investigations were carried out for the company Baxi A/S.-Development of an ideal solar tank. This work was carried out for the company AquaHeat I/S.-Test of a solar collector with and without an antireflection treated glass as cover. This investigation was carried out for Sunarc A/S. SOLAR ENERGY TECHNOLOGIES: Different solar energy technologies were evaluated with regard to energy savings, costs, durability, energy pay back time etc.