Daalderop’s Combinair air-to-water heat pump with gas combi-boiler.
Through clever engineering, Dutch OEM Daalderop
achieves significant efficiency improvements with minimal extra cost
and installation effort.
It may not seem like rocket science:
combining an air-to-water (exhaust air) heat pump with a traditional
gas combi-boiler. Still, by clever dimensioning the Dutch manufacturer
Daalderop (www.daalderop.nl) was able to engineer the Combinair to
achieve significant efficiency improvements with little in the way of
added cost or increased installation effort.
heat pump uses exhaust air from the ventilation system and combines it
with outside air. The heat from the condenser is combined in the boiler
and used in the space heating water circuit.
recently, it was widely assumed that you needed low-temperature floor
heating and a low-energy house when using a heat pump, which made
installation in existing houses unattractive. The modest capacity of a
heat pump was also seen as an obstacle.
the engineers at Daalderop decided to perform lengthy field tests in an
existing, average house. They found that the required average heating
power was quite low (in a mild climate, that is), contrary to popular
belief. They also found that the room-heating capacity of the
gas-fueled boiler will be needed only a few months per year, for an
estimated 10% of the total heating power. The low temperature of the
water was less of a problem than expected; it works well in newer,
well-insulated houses. But they also found that many older houses have
large-surface radiators whose capacity was not fully used because of
The heat pump uses about 150 m3 of ventilation air per hour, resulting in 1 kWh, and 300 m3 of outside air.
pump output is 2.5–3 kW, using 600 kW electric power. In a
well-insulated house in a mild climate, energy savings up to 50% can be
achieved, and a renovated house will see savings of 30–40%. Research
showed that at an outside temperature of 9°C, savings can go up to 70%.
is especially proud of the easy installation: you only need a larger
air inlet and outlet, and no extra ventilation channels or floor
heating. Installation is not error-prone and, in fact, not much
different from existing methods, so installers will feel confident to
use the Combinair. The boiler has a dual heat output, for separate
heating of a study or a bathroom.
other manufacturers not come up with this solution? That’s unknown—and
now it’s too late, thanks to Daalderop’s new patent. “We all made the
mistake of focusing on traditional ideas of heating, and looking at
maximum capacity in cold winters,” Peter van Waarde, export manager,
tells APPLIANCE magazine. “But a heating capacity of 20–30 kW is seldom
used. Instead, we focused on testing at moderate temperatures and found
that the heat pump capacity is sufficient for most of spring and
autumn. And because of minimal installation efforts, you have a payback
period of only three to five years, which is much better than other
Waarde notes that there is another
alternative: the air-to-air heat exchanger, which warms incoming air
with exhaust air. “This solution never really caught on because of
general complexity and installation efforts, and it is not integrated
with the heating/domestic hot water boiler,” he says. “We are proud
that our solution tackled exactly these problems.”
Correspondent Paul Roggema is based in Amsterdam and travels
extensively to report on the appliance industry throughout Western and
Eastern Europe. Read more of his Europe Reports at: