SteamyTea

Had that once, took ages to work out what it was.

Can you plug in a small, cheap, dehumidifier every evening?

Seems your system is working right. Do you collect data all the time on the air temperatures? Phew, got away with it. And you have a nice cosy house.

Good luck with that, if you think it is hard to find someone that knows about ASHPs you will really struggle to find someone that has experience with multiple heat sources.

Bit of education and guess work. The airflow though the heat exchanger will be fairly rapid, so the air will not cool too much as the volume will be quite high. Though at 95% RH, it may well happen, but on a very small scale. Could well happen if the fan stops. And it may have frosted up, Joe90 has not reported back.

The sun is still low this time of year. 23.74° at noon yesterday, will be 59.82° on the 20th June.

@joe90 Quick check before bedtime 23:30PM Your dewpoint temperature is now at 1.4°C, your outdoor conditions are 1.9°C and 95% RH, So looks like you should not freeze up. But only by the skin of its teeth.

Oversize the heat pump. why sizing is so important and cannot be directly compared to a thermal boiler. They work different ways. But you should be able to get a flow temperature above 25°C easily.

Your dewpoint temperature is now at 3°C, your outdoor conditions are 6°C and 81% RH, so a while to go.

Unless there is a real constriction of airlflow, not really. Image putting a fan heater in an alleyway, you would not have to be far away before you cannot feel it.

Not really, they draw in lots of air, not sunshine. So while it may feel, to a person, hot in the sun and cold in the shade, the air is at the same temperature.

@TonyT Be interesting to do an energy analysis on it. As a general note, can't remember much talk about ASHPs actually frosting up in previous winters. @joe90 Be interesting to see if it frosts during the day. Your dewpoint temp is currently 5.2⁰C. 10⁰C here at the moment and quite pleasant. Was going to post a picture up, but seems the forum has got a problem. https://postimg.cc/Jt2JTzZR

I am intrigued. Are you, in effect, preheating the air going into the heat exhanger?

Was popular in the 1960s to do this in flats, was because energy was going to be too cheap to meter. The problem may be that an element will be running at a higher temperature than a liquid system, this may cause hot spots. Easier it heat a liquid first and then pump that around.

Where would you place it, can't cover the heat exchanger. Also it is cheaper to use stored water that has been heated at a CoP of say 2, rather than use an element that has a CoP of 1. Even if it does hurt to have your hard won hot water pumped around the heat exchanger.

You all know what I am going to say, so shall not bother. I have suggested to @PeterW that we have a basic plumbing explanation thread/blog.

At 4°C, water is at its most dense, but water can also exist, in gaseous form, well below 0°C. Ice is a pretty good insulator, at -5°C (we should really be using the kelvin scale), it has a conductivity value of 2.25 W.m-1.K-1. But more importantly, it reduces airflow. The problem is that one ice has formed, the energy to change state is very high, ~330 J.g-1. This means that it can take a long time to defrost if just relying on ambient temperature, and why it is often more economical to just pump some preheated water back though the external heat exchanger. This is because some of the ice will fall off, so does not need defrosting. One way, and something that @joe90 and myself have talked about in the past, is to stop, or reduce the power of the ASHP when the conditions are right for ice formation. But as he has, until this winter (the coldest January in a decade apparently), never noticed it frosting, the idea rather got forgotten. I still think there is some merit in the idea if you know that the temperature will go below freezing later and you can play catch up then.

It also allows elimination of where the water is coming from. If the external temperature and RH levels are high, then that may be where the condensation is coming from, but if they are low, it might mean that the condensation is coming from inside the house i.e. extension still 'drying out', leaking pipe, broken drain, inadequate bathroom/kitchen air extraction. Water can get in all sorts of places. Took me 4 years to find out why my window was leaking, it was a crack in the render several metres from the window. When you ventilate you do not have to have a window fully open, it is not all, or nothing. So you can ventilate without loosing all the heat. So you can heat your bedroom at night, and ventilate, without getting too hot. I often wonder why people close bedroom windows when they go to bed, then open them up in the morning. Ventilate when you are in the room, not after you leave. Stop the problem before it is a problem. Understanding the physics of condensation is not really difficult, but we have Psychrometric charts to help. And formula to establish at what temperature the water vapour turns to liquid, and how much water there will be. Without knowing where you are starting from, you cannot establish if the problem is external or internal. This is why measurements are important. Measuring does not, in itself, cure the problem, it just helps decision making. Refusing to take any measurements means you are just hoping to stumble on the reasons, and there are, when it comes to atmospheric science, an infinite number of permutations. Here is a Psychrometric chart, notice that the lines are not straight, so even a small change in temperature can cause problems.

Better off fitting then horizontally (but keep them clean) as they can take advantage of scattered light on a dull day. There is too much reliance on direct beam irradiation in my opinion.

All turbines have to be up high, that is where the wind is more consistent. That is why they are up high. I cannot see the advantage of fitting a PV module vertically against a wall, especially a south facing one. But you can see what will happen if you go to PVGIS and set the angles and see what comes out.

You are. Small winturbines are very inefficient, and ask yourself why most turbines are horizontal axis ones with blades, and very large The cheapest renewable energy is currently photovoltaic.

Baby steps are needed.

I believe you have a damp/condensation problem. What I do not understand, is your total reluctance to help yourself when help is offered. I bet there a a number of people on here that could turn up at your place and isolate the problems pretty quickly. But you would not allow that to happen. So ask yourself why you are posting up problems that you then do not want to investigate the cause of.

I have just changed my name to the Scanwegian sounding 'Yours'.

But you also poo pooed my request that you collect some data. You just seem to think that it can only be your climate, so impossible to change. You have the kits to collect data, it costs nothing, and may reveal that, even though, your internal temperatures are low, they are not low enough to cause a serious condensation issue. Which you suggest that you have another problem that needs hunting down. BUT YOU WILL JUST NOT DO IT