High Altitude Heat Pumps

[Grog]

Interested to hear from engineers who may have installed heat pumps at altitude or at lower ambients while staying within recommended parameters and any associated problems encountered. Have installed refrigeration equipment in many varied and extreme conditions and locations, but know and realise the limitations of heat pumps.
I know at times we fine tune and 'tweak' refrig plant to get that last degree, but what boundarys have been successfully pushed with heat pumps in regard to altitude and ambients while maintaining our customers trust, and staying close to manufacturers specifications?

[NoNickName]

Hi grog. We, as most manufacturer, recommend to install heat pumps at an altitude not higher than 750m asl. For the ambient temp, most manufacturers declare data at 7°C WB. I would not install a heat pump in a place where the *average* weighted daily temperature is below 7°C DB.

[nh3simman]

We have made our own heat pumps and bought/installed standard heat pumps from the East.

At altitudes of 1800m I have experienced no problems.

From the fan laws, you know that the air volume is constant.

At 1800m, the air density is about 20% lower. This means that the air has 80% of its sea level capacity rate.

But refrig systems are very forgiving in this respect. The suction drops by a small amount and finds a new balance point. The result is only about a 5% drop in capacity.

In reverse cycle mode, the outdoor coil is the evaporator and the suction temperature drop may cause icing in the coil.

In general, I see no problems with running heat pumps at any altitude or ambient condition. As long as you select the components to suit the conditions.