ASHP, MVHR, PV and EV combo

I take it you are fitting a bigger solar system than 4kw? 

What does the CT clamp do? 

Thanks. 

16 minutes ago, Sandybay said:

I take it you are fitting a bigger solar system than 4kw? 

What does the CT clamp do? 

Thanks. 

Hi @Sandybay

Yes the system is 5.12kW max.

 

We had to apply to our Distribution Network Operator (DNO) for permission even though the system will be limited by the CT clamp to a 3kW feed into the grid because the system has the ability to produce over 5kW. we are still waiting for permission. The DNO advised that a decision may take 3 months!!!

 

CT clamp. Yes this irritated me for a while. 

 

As I understand it, a Current Transformer (CT) clamp, can measure the current (wattage) flowing through the cable it is attached to. In this set up it will measure the current passing along the cable in between the consumer unit and the main electric meter. As the AC power goes through the cable the coil in the CT clamp produces DC power. The power runs along the CT clamps cable to the inverter. The inverter can work out how much power is being sent into the grid. When more power is potentially able to go into the grid than the level set the inverter restricts the power output.

 

When using the inverter it works out which way the current is flowing; otherwise it would register the current coming from the grid, however some other devices don't and the CT clamp need to go the right way.

 

Good luck

 

Marvin

 

 

 

Hi, 

Thanks for the reply, 

Am. Looking at a smaller system myself so appreciate the information ?

I'm also considering a Cool Energy ASHP - the larger one. Hopefully they will be around to honour the warranty!

 

I notice you've mentioned pumping to showers - what is the setup you're having there?

 

I ask as I have 3bar where my UVC will be but most important shower is 2 floors up so may lose 1bar+ on the journey up and thinking what to do to ensure good shower performance.

Hi Adam

 

We completely renovated our bungalow in 2018, but with no mains gas ran an LPG bottled gas boiler.  We know exactly how much we used and pretty much when as the bottles needed changing. We oversized our radiators at the time because we were not sure how good our insulation and airtightness would be. We have about 100 square meters of floor and used about 35kWh per m2 for heating and we estimate about 2 to 3 kWh a day hot water.

 

I have a 206 litre vented hot water tank, with a salamander CT50XTRA pump (1.5 bar) giving middle power water to two showers in the bungalow. 

 often sold with) unvented cylinders. The ASHP uses a coil in the cylinder so it would not effect your hot water pressure. 22mm copper all the way up with as few bends as possible , and the hot pipe insulated all the way.

 

Having now run the ASHP for about a month, I would say that there is a lot of understanding required to know how to get the best out of a system.  We have not finished playing with the emitters (radiators and coils) yet as were running it through coils in the MVHR as well. 

 

I believe the first two most important things when considering ASHPs are the thermal resistance and airtightness of the building and correct calculation of the heat loss. Once you have this then you can move on.

 

Good luck

 

Marvin