Hot water heating for the Czech Pavilion at EXPO 2015

We decided to show in the Czech Pavilion how solar heat can be used for heating water which brings substantial savings in electricity expenditures, and at the same time it helps save our environment and minimize greenhouse gas emissions.

Thanks to a continuous system monitoring we were able to evaluate the utilization of our renewable energy technologies. During the 6-month operation of these technologies, the following was saved in water heating at the Czech Pavilion:

  • 17 MWh of electric energy
  • 20 tons of CO2 emissions
  • 82% of electric energy costs

During the 6 months, about 2.5 million visitors passed through the Pavilion, using several restaurants, toilets and showers. The main hot water consumers were primarily the restaurants. The overall daily hot water consumption was between 1000 and 1500 l.

Water was heated up in two storage water heaters mainly from solar thermal collectors. During cloudy periods was is the heat pump that acted as a backup heat source, gaining heat from the ambient air. However, the heat extracted from air originates from the Sun as well because our atmosphere is heated exclusively by the Sun.

Technical description of the system

We installed eight KPG1 solar collectors on the flat roof of the Czech Pavilion on a surface of circa 9x9 m. The collector azimuth had a minimum deviation from the South, and the inclination was 30° against horizontal plane.

Solar energy was changed to heat and transferred from the collectors by Solarten heat transfer fluid to heat water in two Regulus RBC 400 HP storage water heaters located in a 2x2 m utility room. The first water heater was heated by the solar thermal system only, while the other one was heated to the desired DHW temperature by Regulus CTC EcoAir 420 heat pump when needed.

During periods of sufficient sunshine, hot water from one storage water heater was pumped by a circulation pump into the other one. Thanks to that, the heat pump remained switched off and the entire volume of hot water needed and its circulation was ensured by solar energy.

Operation of the whole system was controlled by Regulus IR30 smart controller. It also registered and sent values of temperatures, flow rates and other values for online monitoring and for an exact calculation of the energy balance.

Using the Regulusroute Remote Access to the controller over the Internet, some parameters could be modified in order to secure sufficient amount of hot water with the best efficiency in relation to momentary needs that had not been exactly defined prior to the operation start.

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