ᐅ Split air conditioning system and mechanical ventilation with heat recovery
Created on: 16 Mar 2023 11:30
R
Rafaelsen
Hello everyone,
Does anyone have experience with a split air conditioning system combined with a central controlled residential ventilation system with heat recovery?
The main question is whether the controlled residential ventilation can distribute the cool air from the air conditioner and how well or poorly this works.
My idea: Because of the simplicity and short distances, I am considering a split air conditioning system with 2 indoor units.
The outdoor unit would be placed on the garage, and from there it is only about 50 cm (20 inches) through the wall into the bedroom upstairs and the living room downstairs. Power supply is also available. I want to avoid major effort and long duct runs to actively cool all rooms. The children’s rooms are not as easy to reach. It would be possible via an external duct on the outside wall, but I want to avoid that for aesthetic reasons.
The house was built in 2018 and exceeds the KfW 55 efficiency standard.
The primary energy demand is calculated at 42 kWh/m² (square meter) and the values from recent years confirm this.
We have 178 m² (1,914 square feet) of living space according to the living space ordinance and about 212 m² (2,282 square feet) of floor area. No basement and a gable roof are present, which explains the discrepancy.
Heating is provided by a ground-source heat pump with a water circuit, which is also equipped with a cooling function.
Cooling via the underfloor heating works satisfactorily and keeps the temperature around 24°C (75°F) even in midsummer.
However, it requires consistent shading and following recommendations. Once the heat has entered, it takes several days for the cooling system to lower the temperature again.
In 2022, we consumed 2,169 kWh of electricity and generated 9,408 kWh of heat for heating and domestic hot water.
The building is therefore comparatively efficient in terms of insulation.
We still want to get advice regarding the air conditioning. Both rooms are about 40 m² (430 square feet), and the question arises whether it makes sense to choose a more powerful air conditioner to have more cold air for distribution?
The controlled residential ventilation also supports this to some extent. In summer, it cools the outside air by a good 8°C (14°F).
The air volume flow is approximately 180 m³ (6,360 cubic feet) per hour on automatic setting.
Would the controlled residential ventilation noticeably distribute the cool air from the air conditioner and cool the other rooms, or would we rather get cooling zones within the house?
Thank you very much in advance.
Does anyone have experience with a split air conditioning system combined with a central controlled residential ventilation system with heat recovery?
The main question is whether the controlled residential ventilation can distribute the cool air from the air conditioner and how well or poorly this works.
My idea: Because of the simplicity and short distances, I am considering a split air conditioning system with 2 indoor units.
The outdoor unit would be placed on the garage, and from there it is only about 50 cm (20 inches) through the wall into the bedroom upstairs and the living room downstairs. Power supply is also available. I want to avoid major effort and long duct runs to actively cool all rooms. The children’s rooms are not as easy to reach. It would be possible via an external duct on the outside wall, but I want to avoid that for aesthetic reasons.
The house was built in 2018 and exceeds the KfW 55 efficiency standard.
The primary energy demand is calculated at 42 kWh/m² (square meter) and the values from recent years confirm this.
We have 178 m² (1,914 square feet) of living space according to the living space ordinance and about 212 m² (2,282 square feet) of floor area. No basement and a gable roof are present, which explains the discrepancy.
Heating is provided by a ground-source heat pump with a water circuit, which is also equipped with a cooling function.
Cooling via the underfloor heating works satisfactorily and keeps the temperature around 24°C (75°F) even in midsummer.
However, it requires consistent shading and following recommendations. Once the heat has entered, it takes several days for the cooling system to lower the temperature again.
In 2022, we consumed 2,169 kWh of electricity and generated 9,408 kWh of heat for heating and domestic hot water.
The building is therefore comparatively efficient in terms of insulation.
We still want to get advice regarding the air conditioning. Both rooms are about 40 m² (430 square feet), and the question arises whether it makes sense to choose a more powerful air conditioner to have more cold air for distribution?
The controlled residential ventilation also supports this to some extent. In summer, it cools the outside air by a good 8°C (14°F).
The air volume flow is approximately 180 m³ (6,360 cubic feet) per hour on automatic setting.
Would the controlled residential ventilation noticeably distribute the cool air from the air conditioner and cool the other rooms, or would we rather get cooling zones within the house?
Thank you very much in advance.
S
steuerlexi4 Sep 2024 09:02Rafaelsen schrieb:
Hello everyone.
Our Panasonic air conditioning system has been running since mid-April, and we are very satisfied.
We installed a floor-standing unit upstairs and a wall-mounted unit downstairs in the living room.
Each with its own outdoor compressor unit.
After some trial and error, we start the units on hot afternoons around 3 p.m.
The living and bedrooms cool down within 10 minutes.
The rest of the house takes about 40 minutes to reach a comfortable temperature.
However, those rooms remain about 1 degree Celsius (2°F) warmer than the rooms with the units.
The ventilation works as expected and distributes the cool air throughout the house.
The electricity consumption is negligible. In June, we used about 60 kWh and the systems ran every day until sunset.
That is necessary! If the units are turned off during the day, the house heats up quickly again. In the evening, once the sun is gone, it stays cool until morning.
Both units are so efficient that you can simply leave them running.
Since the house cools down so quickly, it doesn’t make sense to run the system all day. Starting it just before returning home is sufficient.
So, we are very happy and can recommend this setup to anyone. 🙂 Thank you very much for sharing your experience! We are planning to install a 7 kW air conditioning unit with a wall-mounted indoor unit at the highest point of our KfW55-certified house. Since the house has a rather open layout, we want to position the unit as centrally as possible to reach as many rooms as possible. The plan is to install it on the north side so that the cool air blows toward the south side. We are optimistic that the cooling capacity will be sufficient to keep the entire house comfortably temperate.
steuerlexi schrieb:
We are optimistic that the cooling capacity will be sufficient to maintain a comfortable temperature throughout the entire house. When running 24/7, the system easily maintains 22-24°C (72-75°F). Naturally, it cannot cool down to 20°C (68°F) within 2 hours.
S
steuerlexi4 Sep 2024 12:45Nida35a schrieb:
When running 24/7, the system easily maintains 22-24°C (72-75°F),
but it can’t cool down to 20°C (68°F) within 2 hours, of course.Do you have any practical experience with this? Is a central location for the split system necessary, or can it, for example, be installed in the utility room?
steuerlexi schrieb:
Can it, for example, be installed in the utility room?In our house, the utility room is the warmest space, with the heating system, freezer, photovoltaic system, washing machine, and dryer.
When the air conditioning is running, the door to that room is closed.
That won’t work. The distribution in a standard mechanical ventilation with heat recovery system is not good enough for that.
If it were stronger, it would blow in even more warm air.
Install a multi-split air conditioning system. That way, you can cool specific areas, such as the bedroom and living room.
Whether 7 kW cooling capacity is sufficient obviously depends on the house. But it should still provide a noticeable effect in an average-sized house.
We have central cooling integrated into our mechanical ventilation with heat recovery system, plus additional split units. Our ventilation system is designed to be significantly larger than usual.
If it were stronger, it would blow in even more warm air.
Install a multi-split air conditioning system. That way, you can cool specific areas, such as the bedroom and living room.
Whether 7 kW cooling capacity is sufficient obviously depends on the house. But it should still provide a noticeable effect in an average-sized house.
We have central cooling integrated into our mechanical ventilation with heat recovery system, plus additional split units. Our ventilation system is designed to be significantly larger than usual.
Similar topics