Perseus Energy 285 at the heart of the first public building in passive standard in Czech Republic, CS06

The AMOS primary school on the outskirts of Prague was the first public building in the Czech Republic to be built to the passive house standard. The school was opened to pupils in 2019, but the whole project has been in the works for almost a decade.
 
The standards for passive buildings have developed massively in recent years, so when the project was finally ready to enter the design phase with the funding granted, all the variables had to become constants for the project to be successfully completed. The total cost of the project was 420 million Czech crowns, or more than 16 million euros at the time. Before the architectural project began, the winning team of architects visited several similar projects in Switzerland, Austria and Finland to learn about the best ideas and existing practices in dealing with such an innovative public building designed specifically for children.

The AMOS school for its operation combines two independent heat sources:

• Heat pumps (air-water);
• Gas boiler.

The passive standard for buildings in the Czech Republic obliges its operators to record energy consumption and monitor reports. For this purpose, Perseus Energy 285 is now installed in the large equipment room in the basement of the building, and every meter: water, electricity, gas, etc. is connected to and monitored by this unit. Each heat pump is also monitored by Perseus Energy. A calorimeter on the heat collector monitors how much heat has been delivered to the whole system. Prior to the introduction of the Perseus Energy 285, multiple PWR25 units were in operation at the site.

Electricity meters are connected to another Perseus Energy 285 unit and separately monitor the energy consumption in the school kitchen, which is the most energy-intensive part of the building, and separate it from the whole building, which is also metered.

This configuration was chosen because the school must deal with specific realities and regulations. The heat pumps initially heat the water to 42-45°C, which is obviously not enough for the kitchen and hot water tanks. The detail here is that air-to-water heat pumps lose efficiency below -5°C, but diminishing returns start somewhere around 2-3°C, which means that the water has to be heated to the higher temperature using natural gas.

The school has 2 pre-heating tanks that are heated only by the heat pumps, and then, depending on the outside temperature conditions and current consumption, the gas boiler is switched on for 2 separate heating tanks. One is used exclusively for the school kitchen and the other is used to heat the common areas of the building. At the same time, electric reed heaters have been installed to increase the efficiency of everything that is further away from the boilers for more than 50 metres of piping.

Water consumption is similarly monitored and controlled. The school is equipped with a rainwater flushing system for toilets. Water is collected in an underground tank under the outdoor playground and pumped to an intermediate tank in the boiler room. Perseus continuously monitors water consumption and in the event of a water shortage in the underground tank, activates the replenishment of the intermediate tank from the water supply line. At the same time, it detects tank overflow using a WLD cable in case of a fault in one of the water ball valves.

All the meters in the building use M-Bus technology, which is easy to integrate with the Perseus Energy units, which support M-Bus natively. 
 
This entire combination of meters and sensors is then connected to the HW portal - a standalone SensDesk Technology portal operated by HW server, HW group's distributor in the Czech Republic and Slovakia. Smart alerts for water, gas and heat are managed through the portal, as well as automated reports monitoring the current status of all meters.

HW group is proud to have its equipment installed in such a landmark project for the Czech Republic and one of the most innovative school buildings in Europe.