ᐅ Climate Control: What Is the Best Approach?

Created on: 15 Jun 2017 20:50
H
Hausbauer1
Hello everyone,

I’m somewhat heat-sensitive. Until now, I have always lived in apartments that would get extremely hot in summer, despite maximizing shading during the day and ventilating strongly with rapid air exchange at night. Those were the days of my childhood spent in a basement apartment, where even in the height of summer the bedroom stayed pleasantly cool.

To get to the point: I definitely don’t want to deal with that in my own home. So, air conditioning is an important topic for me. My question is: what is the best way to maintain comfortable temperatures even in the peak of summer?

I have read that heat pumps can also provide cooling through underfloor heating, although the effect seems to be relatively mild. It’s also said that mechanical ventilation with heat recovery can be combined with cooling, but here, too, there are obviously fairly strict limitations. Finally, there is the conventional split air conditioning system, which certainly cools well but also consumes a lot of electricity. However, combined with solar panels on the roof, electricity costs should remain manageable since there is usually a surplus of electricity in summer that’s hard to use otherwise.

What would you recommend considering both cost and comfort? Maybe some combination makes sense, for example cooling with a heat pump via underfloor heating and additional cooling through mechanical ventilation with heat recovery – perhaps a moderate amount of cooling from two systems is sufficient in combination. Who has experience and can share knowledge and opinions?

Best regards,
HB1
H
Hausbauer1
29 Jun 2017 13:58
merlin83 schrieb:
Here’s what I’ve thought through:

1: This summer hasn’t been truly hot yet. Neither was the last one. Two or three years ago, we had almost 40°C (104°F) for days on end. Talking to people who have well-insulated homes, there’s no more insulation to add; the heat just stays inside and can only be partially ventilated out without air conditioning. Thick insulated masonry helps release the stored heat more slowly.

2: Ceiling or floor cooling only manages small temperature fluctuations (also because condensation must be avoided). So it’s not very effective if the house is regularly left open.

3: Cooling through ventilation doesn’t work because the air volume is far too low.

4: Air conditioning uses electricity, that’s true. Here’s a calculation: a 10 kW system is sufficient for the bedroom, two kids’ rooms, and living room. The 10 kW is roughly calculated with an efficiency factor of 4. Additionally, there’s a simultaneity factor averaging around 0.4 (meaning only 40% utilization because rarely is everyone home at once). If I calculate 1,000 operating hours, I get:

1,000 hours x 10 kW Ă· 4 efficiency x 0.4 simultaneity factor = 1,000 kWh x 0.21 Euro = 210 Euro per year -> that’s less than 20 Euro per month. How much would you be willing to pay for a cool home at 40°C (104°F)?

5: The 1,000 hours include heating phases. Another advantage of air conditioning is that it not only cools quickly and effectively but also heats quickly and effectively.

The system costs about EUR 9,000 including tax here.

Anytime again!

That would be worth it to me. Sometimes in summer I actually feel relieved when the weather is bad because then the house finally cools down. That’s unpleasant. And I’d be willing to pay 10 to 15 Euro for a good night’s sleep. Not to mention it’s also more comfortable in the living areas.
M
matte
1 Jul 2017 09:55
Mycraft schrieb:
Same here...we actually pay about four times as much

Could you please explain that in more detail? I just can’t quite imagine you have €800 (about $860) in electricity costs per year solely for the air conditioning... I’m calculating roughly €100 (about $110) per year per indoor unit.

At the moment, I’m leaning towards installing air conditioners in the bedroom and office that share one outdoor unit, and possibly an additional separate unit in the living room with its own outdoor unit.

Is your air conditioning integrated into the bus?
Mycraft1 Jul 2017 10:09
We have many south-facing windows, and during a warm Berlin summer, the temperature can reach around 800°C (1472°F)... the system runs continuously. It doesn’t make sense to turn it off and let the house heat up again (for example, when you are not at home) because you want to have a cool house again in the evening.

The system is unidirectional on the bus, meaning I can control it via the bus, but I don’t receive any status messages from the system itself. However, by monitoring the power consumption and temperatures, you can tell from the bus whether the system is running or not.
M
matte
1 Jul 2017 10:14
Thanks for the information. That does surprise me a bit. Are you using external shading? What type of air conditioning units have you installed?
How many indoor units are operating with around €800/year?

Thanks for your help.
S
Steffen80
1 Jul 2017 10:28
Well, I’m curious to see how it will turn out for us. The costs don’t really matter to me. Each interior component has a KNX module and is directly connected to the bus.
M
merlin83
1 Jul 2017 20:44
The 10 kW outdoor unit from Mitsubishi can supply up to 4 indoor units. In many cases, one outdoor unit would be sufficient. In our case, that means 3 bedrooms and 1 living room. Adding an office would only be possible with significantly higher costs.