Solar Thermal Cooling on the Northernmost Latitudes

Abstract

The national priority axis is increase of renewables (RES) use in Latvian Energy sector; therefore, new solutions for Electricity, Heat and Cold production are sought for. Solar energy is available at the same time when there is need to cool rooms, so Solar Cooling systems are suitable also for Latvian conditions. In Latvia such systems are not used yet, so it is important to assess the potential of these systems. The sunlight duration and intensity depends on the season, weather conditions and geographical position of a country. As compared with the annual global solar radiation incident on horizontal surfaces in sunny regions (2200 kWh/m 2 ), in the northern Europe is half as much (1100 kWh/m 2 ). The solar energy potential defined for Latvia as technically achievable by 2020 is: for electricity 0.01 TWh and for heat 0.04 TWh. As shown by experimental studies, the application of solar collectors in Latvia can give good results. The energy of solar radiation can be employed for 1700-1900 hours annually. Due to a gradual increase in the comfort level, the demand for space cooling will grow in the near future. Solar cooling can be an alternative for electrically-powered compression-type chillers that currently are the most common in the Baltic States. The solar cooling system installed in the Institute of Physical Energetic is the first of the type in EU which is built at the latitudes higher than 55 degrees of north. Taking into account the fact that there were no systems plants of this type at so "cold" latitudes, first of all the models in PolySun were to be validated, and a dynamic simulation program containing the five-years meteorological data was to be developed. The solar cooling system has been optimized using multiple simulations. The influence of the system's different elements on its operation is evaluated. The optimal model developed for the given climatic conditions is described.

Performance analysis of solar assisted ground coupled heat pump system in Latvia

“…These collectors must be periodically re-evacuated and re-filled with krypton. In Latvia global solar irradiance is 1100 kWhm -2 , in cloudy period 350 kWhm -2 , but in winter 200 kWhm -2 on average [2]. Heat energy produced in one-hour period by solar collector system is calculated by equation.…”

“…Unfortunately, the solar radiation duration and intensity depend on the season, weather conditions and geographical position of a country. As compared with the annual global solar radiation incident on horizontal surfaces in sunny regions (2200 kWhm -2 ), in the northern Europe it is half as much (1100 kWhm -2 ) [2]. While for solar thermal system, the highest efficiency rate (during the cold season) is limited to the January-March period, and the lowest between November and December.…”

Latent thermal energy storage for solar driven cooling systems

“…Heat was used for thermal driving chilling; this heat was mainly derived from the solar thermal system. In this case, the solar thermal system with thermal power 15 kW at ΔT = 70 K was used [10]. One cubic meter storage tank with 8kW electric heater is included in the solar thermal system.…”

Investigation of Performance of Solar-Assisted Heat Pump Systems: Muğla Example

“…They optimized the solar cooling system using multiple simulations. They evaluated the effect of different elements of the system on the operating performance and developed the most suitable model for the given climate conditions [12]. Good et al (2014) used POLYSUN and PVsyst programs to optimize the solar energy potential in buildings [13].…”

“…Ghafoor and Fracastoro (2015) used the POLYSUN program in their multi-purpose solar thermal systems to compare their cost effectiveness with multi-purpose PV based heat pumps [11]. Shipkovs et al (2015) assessed the models found in the POLYSUN program in the northern latitudes and developed a dynamic simulation program containing 5 years of meteorological data. They optimized the solar cooling system using multiple simulations.…”