Guidelines for design of seasonal pit heat storages.

The factsheet gives a high-level definition of designing solar thermal systems for district heating. In addition, modules are introduced which can be used for modelling systems and finally, methods for estimating energy yield and costs of systems are described.

Investigation of measured long-term field performance in relation to standardized collector test information and tools/models for annual performance prediction at different operating conditions and field designs.

Solar radiation data is necessary for the design of solar heating systems and used to estimate the thermal performance of solar heating plants. Compared to global irradiance, the direct beam component shows much more variability in space and time. The global radiation split into beam and diffuse radiation on collector plane is important for the evaluation of the performance of different collector types and collector field
designs.
 

Solar collectors are the core components of solar district heating plants. Annual solar heat yield of solar heating plants on average is around 400-500 kWh/m2 in Denmark. Most solar collectors in the large solar district heating plants in Denmark are ground-mounted flat plate collectors. Arcon-Sunmark A/S is the main manufacturer of the large flat plate collectors for district heating in Denmark. Arcon-Sunmark A/S has installed more than 80% of the world’s large solar heating plants connected to district heating networks.

By the end of 2017, solar heating plants with a total surface of more than 1.3 million m2 were in operation in Denmark. Most solar collectors in the existing solar heating plants are typically flat plate collectors (FPC).
 

Large collector fields are increasingly being integrated into district heating systems. Due to the operation mode of these networks, the solar system must provide the desired supply temperature. Therefore, knowledge of thermal-hydraulic behavior and energy efficiency are very important for planning, operation and control. The study presents the investigation of two large-scale solar collector fields in Chemnitz (Germany).