| Work Detail |
Arriba Technologies, a UK heating and cooling specialist, has developed a solar-integrated heating and cooling unit with a DC electrical system, all in a single package. It is installed at a 750 kW plant at Cambridge’s Rosie Hospital and won the Lighthouse Heat Pump Award at the European Heat Pump Association’s heat pump forum in September.
UK-based Arriba Technologies, a solar-boosted heating and cooling specialist for the commercial and industrial market, has developed a solarized heating and cooling system that uses DC power connections.
The technology’s largest-scale deployment to date is at Cambridge’s Rosie Hospital. Designed as a “Swiss Army knife” solution, the 750 kW facility features interconnected heat pump-chillers that provide the hospital with all its heating, cooling and domestic hot water, without the need of a backup boiler, alongside an integrated DC electrical system and solar power conversion in one pre-built package.
The design is noteworthy for its high amperage DC power system, which runs electromotors fitted to the plant’s compressors, fans and pumps from a 650 V DC power system, that is in turn energized by the local 400 W grid and a dedicated 80 kW solar array. Energy flowing into the 650 V system is managed using four 20 kW DC:DC converters and two AC to DC rectifiers.
The unit has been in operation at the hospital since September 2023. On average, the design draws between 10% and 90% of its primary energy during daylight hours from a DC-coupled 80 kW solar array, located 40 meters away from the heat pump-chillers. Steve Connolly, the CEO of Arriba Technologies, told pv magazine that even into October, the plant was still seeing periods where all the hospitals heating and cooling needs were powered by the solar panels on the roof.
After one year of operation, the design has delivered immediate running cost benefits to the hospital and contributed to its net zero plans, with the building achieving better carbon efficiency than comparable buildings across the National Health Service estate.
The project won the Lighthouse Heat Pump Award, awarded to innovative and creative heat pump projects, at the European Heat Pump Association’s annual heat pump forum in September.
Connolly told pv magazine that by taking power from solar grids on a DC power line, and skipping out some of the conversion steps, at least 6% better efficiency can be achieved. He added that this can be further doubled with good software.
The software and controls system used in the Rosie Hospital design were developed from earlier versions of similar systems that Arriba implemented on previous solarized heating, ventilation and air conditioning (HVAC) installations, which the company said is unique in the field of heat pump and HVAC engineering.
“The advantages for the customer are that it’s a fully worked up product,” Connolly said. “We know it works to a very high level, and for the customers it derisks what could otherwise be a daunting prospect, to wire up on 600 V DC system. But when its all hidden in a box and when its proven to work, at quite a scale and in a very important building, it demystifies the technology.” |
