Renewal of Zöld Liget Kindergarten’s Heating System

The Pestszentimrei Zöld Liget Kindergarten is one of StepUP project pilots, aiming at demonstrating the viability of plug & play technologies for deep renovation. After a first renovation phase to ensure a thermal insulation of the facade and the roof, the works continued to renew the heating system, actively contributing to reduce the building’s energy consumption.

The assessment by the design team revealed that the central heating system, provided by an open combustion, atmospheric hot water boiler, was outdated and its operation was unreliable, as were the cast iron sectional radiators and steel pipe network installed approximately 60 years ago.

The renovation began with extensive demolition work, during which we dismantled the old heating pipes and radiators. During the renovation, the old gas boiler system was replaced with an energy-efficient heat pump system. The heat pumps are capable of both heating and cooling, and can produce water with a flow temperature of up to 60°C even on the coldest winter days.

The building’s heating energy demand decreased by 32%. We estimate that a total energy consumption reduction of 77% can be achieved.

Additionally, a solar panel system was installed on the roof, capable of covering the average energy consumption. The maximum utilization of the solar panels is easily achievable thanks to the smart grid-ready heat pumps. The solar panel system consists of a total of 45 pieces of 410 Wp monocrystalline solar panels, with a total installed capacity of 18.45 kWp, and a slope angle of 45%. The expected average annual production of the system is: 13,625 + 6,681 = 20,306 kWh.

Installation of PV panels on the kindergarten roof

If the solar panels generate surplus energy and the heat pumps also produce excess energy, it is stored in buffer tanks for later use. The buffer tanks are HeatVentors HeatTank storage units, based on phase change materials, individually sized, and manufactured by the manufacturer for the specific project. HeatTank Thermal Battery system, one of project Plug & Play technologies, is a solution to produce heating or cooling energy when it is the most efficient, when it is the cheapest, or when waste heat sources or renewable energy sources are available. The hot water supply is also provided by this system.

For the optimal energy consumption and maximum comfort, the heating and cooling of the entire building are ensured in combination with radiators and fan coils. The installation of the fan coil heating and cooling system always involved the installation of quiet, low-speed fan coil units. The distribution of the heating and cooling main pipes was done with freely installed pipes. For aesthetic reasons, the pipe system was covered with false ceilings in several places.

View of a kindergarten classroom after renovation

The inverters were equipped with smart meters for later better control and higher degree of self-sufficiency. The renovation was completed with the replacement of the old parquet flooring and the painting of the walls.

According to calculations, the building’s heating energy demand decreased by 32% just due to insulation, and a total energy consumption reduction of 77% can be achieved through the  renovation.

On March 26, 2024, we concluded the StepUP project with a small ceremony, marking the completion of the renovation process at the Pestszentimrei Zöld Liget Kindergarten:


Author: BP18 Municipality

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 847053.

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