Article in “Kälte Klima Aktuell”
SUSTAINABLE AND SECURE IN THE FUTURE
For the construction of a new office and administration building at its headquarters in Neckarsulm, Bechtle AG decided to dispense with HFC refrigerants for reasons of sustainability. The company invested in an environmentally friendly and energy-efficient heating and air conditioning solution with reversible propane air-to-water heat pumps and air-cooled R290 chillers from Skadec.
The trend towards using natural refrigerants for sustainable and resource-saving cooling and heating generation is being recognised by more and more companies. Many operators are not even aware of the fact that natural refrigerants and the components required for them are actually nothing fundamentally new on the market. For almost 150 years now, refrigeration machines have been operated with natural refrigerants such as hydrocarbons. Skadec has been researching the use of propane (R290) in its machines for many years in order to offer its customers this environmentally friendly and therefore future-proof option for operating cooling and heating systems. R290 is particularly suitable as a refrigerant for use in reversible air-to-water heat pumps. Based on its many years of expertise, the Baden-Württemberg-based company is now developing R290 heat pumps that achieve significantly better energy efficiency values than conventional heat pumps, which are predominantly operated with the climate-damaging synthetic refrigerants R410A, R32 or R454B.
A MODEL STUDENT NAMED PROPANE
R290 is a naturally occurring gas whose negative impact on our environment is minimal. It has a very low GWP (Global Warming Potential) of 3 and an ODP (Ozone Depletion Potential) of 0. Due to its high energy efficiency and the low price of propane, the chillers and heat pumps are cost-effective to operate and service. In addition, R290 will not be affected by future bans under the F-Gas Regulation due to its environmentally friendly properties.
A major advantage of R290 is its wide range of applications with high outlet temperatures, even at low ambient temperatures. For example, an outlet temperature of 65 °C can still be achieved without any problems at an ambient temperature of -15 °C. And all this with an impressively low refrigerant charge in the system. A 400 kW R290 heat pump with three separate refrigerant circuits only has a charge of around 15 kg per circuit. By comparison, an R32 (GWP 675) heat pump in this output range requires a charge of around 85 kg. This corresponds to a CO2 equivalent of 57.3 tonnes for R32 and 0.135 tonnes for R290.
The only drawback is that R290 is categorised in safety class A3 due to its flammability. While most suppliers on the market therefore prefer to continue using refrigerants that are harmful to the climate, Skadec is able to convince many operators to use R290 thanks to its well thought-out safety concept.
KNOW-HOW FROM HOHENLOHE
Skadec launched the innovative technology of reversible R290 heat pumps on the market back in 2016 and therefore has the most experience in the field compared to its competitors. The product portfolio now includes systems in the 30kW to 400kW heat output range. Reference systems in Scandinavia and Eastern Europe have already proven themselves in heating operation at ambient temperatures of -18 °C and demonstrate the desired reliability. In order to guarantee its customers a high standard of quality, Skadec heat pumps are also manufactured for foreign customers in accordance with the German industrial standard and the control cabinets are wired in accordance with the VDE standard. Only components from well-known manufacturers are used.
As with conventional heat pumps, operation is based on the cold vapour process. The systems are equipped with frequency-controlled compressors, EC fans, a closed machine housing and a PLC machine controller as standard. The intelligent control system developed in-house regulates energy-efficient operation and needs-based defrosting by means of a circuit reversal with a 4-way changeover valve. From an output of around 50 kW, the heat pumps already have two separate cooling circuits, which increases operational reliability and failure safety. In order to provide the customer with the best possible support during operation of the system, all heat pumps are monitored in real time via integrated remote maintenance as standard.
CUSTOMISED SYSTEM SOLUTION FOR THE MARKET LEADER
Part of Bechtle’s 2030 sustainability strategy is to act in harmony with the environment in favour of a future that protects the climate and conserves resources. The company has therefore made a conscious decision in favour of a sustainable solution. Now that the systems for heating and cooling with R290 have already gone into operation in 2020, we want to take a closer look at this successful project.
The heat required in the building is generated by two reversible air-to-water heat pumps. These each have a heating capacity of 125 kW at a standard outdoor temperature of -14 °C and a cooling capacity of 175 kW at an outdoor temperature of +35 °C.
A master controller supplied by Skadec regulates the efficient operation of the systems. For example, all circuits are operated in energy-efficient partial load mode wherever possible and switching cycles are avoided. Each of the two heat pumps has two separate refrigeration circuits and frequency-controlled reciprocating compressors from Bitzer, which have been specially optimised for operation with R290. Inside the closed machine housing, which significantly reduces noise emissions, there is a leakage monitoring system, which in turn activates an EX-protected housing ventilation system in the event of a leakage.
To cool the building, two additional air-cooled R290 chillers were installed, each with two separate cooling circuits and frequency-controlled compressors. All four systems are controlled via a PLC and are connected to the Skadec remote maintenance system so that they can be monitored by the customer service centre. In the event of a fault, the customer is proactively informed and, if possible, the problem is rectified directly from the office.
ECOLOGY AND ECONOMY HAND IN HAND (only available for projects located in Germany)
The Federal Office of Economics and Export Control (BAFA) subsidises refrigeration, air conditioning and heat pump systems that conserve resources and the environment. In this project, in addition to the four R290 heat pumps and chillers, the components and the overall system were also subsidised, including the pipework network, buffer storage tank, recirculating air cooler and planning.
The project presented shows that propane is an ecologically very sensible and future-proof solution for generating cooling and heating. On the other hand, the economic aspect is always important for operators. In addition to the BAFA subsidy, there are other subsidy options.
Click here for the article on the website of the Kälte Klima Aktuell (only available in German).
