High-performance air-to-water heat pumps
Cutting-edge heating solution for a sustainable residential development
Künzelsau, GermanyThe town of Künzelsau is located in the Hohenlohe region in the north east of the state of Baden-Württemberg, and is the hub of the Heilbronn-Franken district. With around 15,000 inhabitants, the town is home to several globally active businesses in industries ranging from mounting parts, ventilation and conveying systems to explosion protection and textiles. This prosperity has led to a high demand for residential space, which in recent years has largely been met via the Taläcker Allee development on the Hohenlohe plateau. The most recent project here was the construction of 80 rental apartments by DH Wohnen GmbH from Denkendorf, which feature a resource-efficient wooden module construction.
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Requirements:
- Highly efficient energy concept
- Low noise emissions
- Compact unit size
Background
Background
Residential property company DH Wohnen GmbH focuses primarily on purchasing and developing land, as well as the planning, construction, maintenance, leasing, management and sale of residential buildings. The company collaborated closely with Aktivhaus, one of the leading general contractors for mass-produced wooden module construction, to build 80 accessible apartments based on 112 wooden construction modules in the new development. With the experience from projects totalling over 35,000 m2 of constructed floorspace, Aktivhaus sets new benchmarks and offers its expertise in planning and constructing sustainable residential buildings to both municipalities and property companies.
Its wooden modules follow the triple-zero principle and offer countless advantages. Wood is a renewable material that binds large amounts of CO2. The modules are designed so that they can later be disassembled completely and precisely into their input materials. The construction materials used are chosen with sustainability and resource efficiency in mind. The modular construction method also shortens construction times, allowing the urgently needed homes to be handed over quickly. In terms of durability, the homes built with this modular method last just as long as a conventionally built house.
Which solution was chosen?
Solution
The apartment blocks in this highly sustainable project were planned and built in line with the KfW 40 EE energy standard. This is possible thanks to a highly efficient energy concept that covers the primary energy requirement through large modern heat pumps in combination with photovoltaic systems. The photovoltaic systems on the roofs of the four apartment blocks even provide a significant proportion of the energy required to run the heat pumps thanks to their regenerative power production. The concept uses four typeMEHP-iS-G07 / 0112air-to-water heat pumps from Mitsubishi Electric that use the outdoor air as an energy source.
Major benefits
BenefitsQuiet, compact and powerful
Made in Europe, the MEHP-iS-G07 series is Mitsubishi Electric’s latest reversible heat pump for large heating needs, and was developed by the heat pump specialists in house. Their development was guided above all by high quality and a focus on detail. The air-to-water heat pumps deliver top-class energy efficiency in a highly compact design. They are among the quietest and most powerful units of their class.
High energy efficiency with inverter technology
High energy efficiency with inverter technology
The heat pumps of the MEHP-iS-G07 series use Mitsubishi Electric’s own inverter-controlled scroll compressors and EC fans. With a COP of 3.2 to 3.5 as per EN 14511, these units achieve high energy efficiency values. Further environmental protection comes in the form of the R32 refrigerant used throughout the units. It has a GWP value 68% lower than that of the R410A refrigerant still commonly used in this product group. These technical features make the heat pumps perfectly suited for use in comfort applications, where they can truly come into their own.
Made for high heating requirements
These units were designed with the heating function as the main focus. Their modular unit structure ensures optimum adjustment in line with the respective capacity requirement for this specific project. This allows them to also be used in local heat networks, for example. Three different modules are available, with seven performance classes ranging from 50 to 110 kW of rated heating capacity and COPs of 3.5 to 3.2 as per EN 14511. A heating capacity of up to 220 kW can be achieved through the optional configuration as a twin module. Encompassing outside temperatures as low as -20°C and hot water outlet temperatures as high as 65°C, the broad application range of these units in heat pump operation means they can optimally meet requirements.
Integrated LAN logic
The integrated LAN logic allows users to control up to eight of these units in a group. This promotes optimum load distribution, alarm management and backup/standby operation of the entire system. The software connection is performed by a multi-manager featuring a large number of smart functions. For example, the heat pump models use the smart defrost logic when multiple units are connected.
Eligible for financial support
Just like many other air-to-water or brine-to-water systems from Mitsubishi Electric, the large heat pumps in the MEHP-iS series are fully eligible for financial support. They require only a small amount of electricity for the drive, which can also be taken from renewable sources such as the photovoltaic system. The heat pumps take the rest of the energy they need from the environment – a free source of power.
Further advantages
BenefitsRedundant system design for greater reliability
The four air-to-water heat pumps are hidden away in noise-insulated housings on the front sides of the apartment blocks. Each housing contains two heat pumps that provide 80 kW of heating capacity. Overall, the system delivers around 320 kW of heating capacity for the four apartment blocks and their 80 apartments at the design temperature in Künzelsau of -12°C. “The systems have a redundant design, meaning that two units form a system that alternates between the two.
There are two technology rooms in the two underground car parks. Here, the hot water from the heat pumps is conveyed into two buffer storage tanks, before being pumped via two distribution stations into the risers”, explains Silvio Braun, project manager at Windmüller Technik GmbH in Schwäbisch Hall. “Stations in the apartments distribute the energy to the heating circuits in the underfloor heating accordingly. The domestic hot water is also generated by the apartment stations, which feature integrated electrical flow heaters.”
Comprehensive maintenance and service agreement
The conclusion of a maintenance and service agreement with the provider was a no-brainer for operator DH Wohnen GmbH, as it offers many advantages. Regular maintenance of the technical system extends the service life and can improve the overall efficiency. It allows system data to be checked, enables settings and operating parameters to be better adjusted to the real conditions, user requirements and environmental influences, and allows wearing parts to be replaced where necessary, for example. “The remote maintenance with preliminary check allows us as the service company responsible for this property to take a direct look at the system from our computer and get a better idea of what’s going on and what is needed”, explains Braun.
The key points
Summary- The four-floor apartment block development with wooden module construction was planned and built to the KfW 40 EE energy standard.
- The highly efficient energy concept covers the primary energy needs through large modern heat pumps working together with photovoltaic systems.
- The system uses type MEHP-iS-G07 / 0112 air-to-water heat pumps from Mitsubishi Electric that are designed and produced in Europe specifically for buildings with high heating requirements.
- These cutting-edge and efficient units are fitted with variable-speed scroll compressors as standard, and use a low-GWP refrigerant.
