ᐅ Active vs. Passive Air-to-Water Heat Pumps: Differences in Cooling
Created on: 6 Aug 2021 08:44
D
Dany250Hello dear community,
First of all, a few words about myself.
We unexpectedly found ourselves back at the topic of building a house due to the very unexpected purchase of a plot of land (we searched for many years and had basically given up on the whole project because of age and the increasingly shorter financing possibilities).
I have been reading quietly and diligently here for the past few weeks, but I still have a question for you and hope you can give me some feedback.
At first, we also considered being convinced by the advertising of some prefabricated house manufacturers and to go with an air-to-air heat pump. However, we have since ruled that out and decided on an air-to-water heat pump instead (I would like to avoid turning this thread into another discussion round about air-to-air heat pumps; I’m not speaking negatively about them, we just decided on the air-to-water heat pump in order to move forward).
We also read that there is a difference between active and passive air-to-water heat pumps. To me, as a complete layperson, it sounds like the active version can be switched to function like a large refrigerator, actively cooling the water in the underfloor heating system. It is said that this variant can cool the climate very well, at least significantly better than the passive option.
We thought we had found our system and wanted to approach prefabricated house manufacturers that offer such a system. However, after reading a lot, you can also find some opposing threads, which is why I wanted to start this thread myself (no situation is the same).
A few words about our situation: We currently live in a multi-family house built in 2014, in the top-floor apartment. Our approximate 90m² (970 sq ft) living space extends almost across the entire attic and includes five skylights that are not shaded from the outside, located under a pyramid roof. To the south, we have a very large roof terrace adorned with a 6m (20 ft) wide window front. The house is situated at about 330 meters (1,080 ft) above sea level in the Stuttgart surrounding area.
During the day, we keep everything closed where possible, but once the heat is inside in summer, we cannot get it out again, meaning we constantly have temperatures above 27°C (81°F) in the bedroom, which simply prevents us from sleeping. A portable air conditioner provides temporary cooling, but already 30 minutes after turning it off, the room returns to the same temperature as before. At night, it is unbearable because it is just too loud.
In other words: we want to do everything better in our new home :-).
The new house is planned to be built with a mono-pitched roof at an elevation of about 300 meters (985 ft), also in the Stuttgart surroundings. The plan is for KfW 40 Plus standard with photovoltaic panels on the roof.
We would like to achieve temperatures below 27°C (81°F) in our upstairs bedroom in the future; ideally between 23°C and 25°C (73°F and 77°F) would be a dream. We are planning a smart home that self-shades with external venetian blinds (also known as louvered blinds). The style will be fairly open, and it will be just the two of us living there. We are thinking about approximately 140 to 150m² (1,500 to 1,615 sq ft) spread over two floors plus a basement (due to practical reasons and the slight slope of the land).
As mentioned before, I have also read that active air-to-water heat pumps don’t work miracles. Could you please tell me if “active air-to-water heat pumps” always mean the type we prefer, specifically with refrigerated water integrated into the floor heating?
Our climate will definitely continue to get warmer, and we plan to live in this house for at least another 30 years. Do you think it would be sensible to equip the house with an air conditioning system from the start? We originally wanted to avoid this and were hoping for cooling via the floor system, but as I said, reading extensively can also cause a lot of uncertainty when making decisions.
We would really appreciate your constructive opinions.
Thank you very much and best regards
Dany
First of all, a few words about myself.
We unexpectedly found ourselves back at the topic of building a house due to the very unexpected purchase of a plot of land (we searched for many years and had basically given up on the whole project because of age and the increasingly shorter financing possibilities).
I have been reading quietly and diligently here for the past few weeks, but I still have a question for you and hope you can give me some feedback.
At first, we also considered being convinced by the advertising of some prefabricated house manufacturers and to go with an air-to-air heat pump. However, we have since ruled that out and decided on an air-to-water heat pump instead (I would like to avoid turning this thread into another discussion round about air-to-air heat pumps; I’m not speaking negatively about them, we just decided on the air-to-water heat pump in order to move forward).
We also read that there is a difference between active and passive air-to-water heat pumps. To me, as a complete layperson, it sounds like the active version can be switched to function like a large refrigerator, actively cooling the water in the underfloor heating system. It is said that this variant can cool the climate very well, at least significantly better than the passive option.
We thought we had found our system and wanted to approach prefabricated house manufacturers that offer such a system. However, after reading a lot, you can also find some opposing threads, which is why I wanted to start this thread myself (no situation is the same).
A few words about our situation: We currently live in a multi-family house built in 2014, in the top-floor apartment. Our approximate 90m² (970 sq ft) living space extends almost across the entire attic and includes five skylights that are not shaded from the outside, located under a pyramid roof. To the south, we have a very large roof terrace adorned with a 6m (20 ft) wide window front. The house is situated at about 330 meters (1,080 ft) above sea level in the Stuttgart surrounding area.
During the day, we keep everything closed where possible, but once the heat is inside in summer, we cannot get it out again, meaning we constantly have temperatures above 27°C (81°F) in the bedroom, which simply prevents us from sleeping. A portable air conditioner provides temporary cooling, but already 30 minutes after turning it off, the room returns to the same temperature as before. At night, it is unbearable because it is just too loud.
In other words: we want to do everything better in our new home :-).
The new house is planned to be built with a mono-pitched roof at an elevation of about 300 meters (985 ft), also in the Stuttgart surroundings. The plan is for KfW 40 Plus standard with photovoltaic panels on the roof.
We would like to achieve temperatures below 27°C (81°F) in our upstairs bedroom in the future; ideally between 23°C and 25°C (73°F and 77°F) would be a dream. We are planning a smart home that self-shades with external venetian blinds (also known as louvered blinds). The style will be fairly open, and it will be just the two of us living there. We are thinking about approximately 140 to 150m² (1,500 to 1,615 sq ft) spread over two floors plus a basement (due to practical reasons and the slight slope of the land).
As mentioned before, I have also read that active air-to-water heat pumps don’t work miracles. Could you please tell me if “active air-to-water heat pumps” always mean the type we prefer, specifically with refrigerated water integrated into the floor heating?
Our climate will definitely continue to get warmer, and we plan to live in this house for at least another 30 years. Do you think it would be sensible to equip the house with an air conditioning system from the start? We originally wanted to avoid this and were hoping for cooling via the floor system, but as I said, reading extensively can also cause a lot of uncertainty when making decisions.
We would really appreciate your constructive opinions.
Thank you very much and best regards
Dany
R
RotorMotor6 Aug 2021 08:59tl;dr: What exactly is supposed to be passive or active in an air-to-water heat pump? Cooling? I don’t see how that would work.
As far as I know, cooling is only possible with a ground-to-water (brine-to-water) heat pump.
The title also doesn’t really make it clear that it’s actually about cooling.
As far as I know, cooling is only possible with a ground-to-water (brine-to-water) heat pump.
The title also doesn’t really make it clear that it’s actually about cooling.
The best cooling (air conditioning) is the one you don’t need. This means the house should be designed from the start to minimize the need for active cooling. Insulation, shading, and ventilation should therefore be considered from the very beginning.
Cooling through the underfloor heating system is passive, regardless of how heat pump manufacturers label it.
Additional note: In the case of ground-source/geothermal heat pumps, it is considered passive; for your air-to-water heat pump, it is active (reversible system).
Choosing providers based solely on heating/cooling solutions is not effective. Reputable suppliers already offer suitable systems within their portfolio.
Cooling through the underfloor heating system is passive, regardless of how heat pump manufacturers label it.
Additional note: In the case of ground-source/geothermal heat pumps, it is considered passive; for your air-to-water heat pump, it is active (reversible system).
Choosing providers based solely on heating/cooling solutions is not effective. Reputable suppliers already offer suitable systems within their portfolio.
R
RotorMotor6 Aug 2021 09:13driver55 schrieb:
Cooling via underfloor heating is passive, regardless of how heat pump manufacturers describe it.
Additional note: In the case of brine/ground source systems, it is considered passive; with your air-to-water heat pump, it is active (reversible system). This is contradictory. First, it’s always said to be passive, then the correct distinction is mentioned. ;-)
Tolentino schrieb:
It is possible with some air-to-water heat pumps, but it’s not very effective. It’s better to plan a dedicated air conditioning system from the start. You’ve already considered external shading, which is actually even more important! Yes, cooling is possible with an air-to-water heat pump, but it’s not passive.
RotorMotor schrieb:
tl;dr: How can an air-to-water heat pump be either passive or active? Cooling? I don’t see how that would work.
As far as I know, that’s only possible with a ground-source heat pump. I have found the following example several times online:
"With active cooling, the entire heat pump cycle is reversed. If an air-source heat pump can extract heat from the outside air, it can also remove heat from the indoor air. Active cooling is suitable for both ground-source and air-to-water heat pumps. The extracted heat is transferred with the help of the compressor back to the original source (e.g., the ground), which acts as the heat sink/cooling body in this reversed process. This actively lowers the indoor temperature."
RotorMotor schrieb:
The title somehow doesn’t make it clear that the topic is actually about cooling. I’m sorry about the title; you’re absolutely right. However, I can’t change it, can I?
@driver55
Does what I wrote in italics sound like a "refrigerator principle" under the floor?
I’m a complete beginner, so please forgive my choice of words regarding the technical terms...
Similar topics