Wastewater heat recovery is the background of energy efficient building

Wastewater heat recovery is the background
of energy efficient building

In general it is thought that the new building is well constructed when it meets modern building regulations. However building regulations are only minimum requirements to ensure a functional building design and construction. The energy consumption of the building can still be higher than the calculated building regulations due to the geometry and architecture of the building. The ratio of the building envelope to the floor area is a significant factor in the energy consumption, but the technical solutions and the consumption of hot water and its heating effect can be as much as half the total energy consumption of the building.

However energy consumption should not be confused with energy costs, which can be significantly affected by the choice of heating and cooling system. Conventional district heating has, to a parallel extent, received various types of heat recovery and heat pump solutions that can reduce building heating costs compared to traditional district heating. This cost difference consists of the development of building-specific heat recovery and heat pump systems, as well as price differentials between district heating and electricity. In general the trend seems to be going in the direction where the heating of buildings will also be electrified in the future just like the traffic.

Often competition between heating systems focuses only on district heating and ground heat. Neither solution in itself is the most efficient heating solution available in the market. The problem of district heating is the more expensive in-use costs and the volatile price monopoly while geothermal energy is many times higher than the cost of district heating, and its efficiency is rather weak in hot water production. So you need to find a product solution that eliminates the weaknesses of both main heating systems. One solution has been for example to extract air heat recovery or solar energy recovery. However in these cases problems often occur on the facades of buildings, especially on roofs, which cannot be used to add building systems that affect the appearance of a building.

Generally it is already known that hybrid systems are the best in the market for heating and cooling solutions for buildings, but should only find the missing piece that will benefit both the district heating and geothermal systems in their shortcomings without the constraints of scraping. The lack of productized solutions has been a problem in the past, but now the Ecohybrid system responds by bringing the missing piece to this equation – the heat recovery of the wastewater. Wastewater heat recovery is suitable for both district heating and geothermal heating systems. Also, the heat recovery of wastewater does not modify the façade or the roof surface of the buildings, so it does not have any drawbacks. Wastewater heat recovery is suitable as an independent system or sub-component for large apartment buildings, hotels, swimming pools, hospitals or industrial plants with more than 20 dwellings, excluding single-family homes and small-town houses.

Wastewater heat recovery does not limit other heat recovery solutions. Exhaust air heat recovery can be connected to the same heat generation system. In fact the best efficiency is achieved by combining the recovery of waste water and extract air heat into the same heat pump alongside district heat or ground heat. The recovery of heat from wastewater and exhaust air alone can reduce the consumption of the main heating system by up to 80%. Due to the remaining relatively large district heat connection and power charges, consideration will also be given to exchanging district heat to a small number of geothermal wells or underground energy piles that are connected to the same heat pump system alongside the waste water converter. This can replace the entire district heating and district cooling connection with the hybrid system.

The wastewater heat exchanger or heat exchangers are usually placed on the ground floor of the building at the point where the building’s drainage lines are either inside or outside the building. The best location is the technical state of the building, where the heating system is located. Thus the location can also be outside the technical space across the building. In general, wastewater heat recovery is placed in the interior of the building, which avoids the freezing of wastewater inside the changer during the winter. In exceptional cases the wastewater converter can be placed in cold outdoor spaces, but in this case it requires spare heating and external protection.