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About this blog

This is a short blog about the thinking process, installation and results of a combined ASHP, MVHR, PV, EV charging and Water heating coil system being installed in a bungalow with good insulation and air tightness.

 

Be warned! The theory, installation and results assumed may not be right and I will only be sure when the job is completed.

 

Should you have any questions about this PM me and I will try to include an answer in the blog.

 

Good luck with your home

 

Marvin

Entries in this blog

Understanding PV energy production variations

Understanding PV energy production variations

Energy production is as variable as the weather. 🙄 But how much does it change the results in a month or year?   Based on calculations using the PGIS data over 10 years I thought I would share the results.  In one calendar year the energy produced can vary from the average by +/- 5%.  In one calendar month the energy produced can vary quite widely!  From +24% to -28% from the average!     Here's my summarised results:                          
PV energy use

PV to hot water and heat storage controls

PV to hot water and heat storage controls schematic:       This system only uses the excess PV power (unless the Solic 200 button to use any power is pressed, and then it will allow any power for 90 minutes).   There are three output choices. Firstly to the hot water tank immersion until the tank reaches the temperature set point, then to one of the two storage heaters as chosen.   Although some people have mentioned that the Solic 200 (other types I
Marvin

Marvin in PV energy use

12
PV energy use

PV EV charger control schematic

This is the latest system we have:       There are 4 CT relay clamps, 3 for the EV charging, (and one will be for battery charging), which are set at different PV output levels depending on the month of the year which decides what rate of PV needs to turn on the charging of the EV. This relates to a 3kW charger and the expected power requirement for the EV on a particular month and the expected production using the PGIS web site calculator.   The summer 3.6kW
Marvin

Marvin in PV energy use

3
PV energy use

ASHP v Immersion with PV

Results for us as they come forward...(and not what I expected)   Our Cool Energy inverTech Air Source Heat Pump CE-iVT9 4.3kW-9.5kW has been on standby only, for the last few weeks, and I have measured the power consumption. It appears to use about 0.1 kWh an hour. That's about 2.25kWh a day in 24 hours.     We use a Solic 200 to direct our excess electricity produced by the PV to the hot water immersion.   Whilst the Solic way of heat the hot water uses more energ
Marvin

Marvin in PV energy use

28
Power storage alternatives

MDi Airwall

Having had no response about the Ridgeblade product, I am now looking towards the MDi Airwall as a form of power storage.   This uses excess energy to compress air and use the compressed air to produce electricity.   The basic unit indicates a 7kwh storage capacity.         
PV energy use

Working on reducing mains power by best use of PV (without batteries).

Having now had a 5.12kW system running for about 6 months, usage seems to be forming a pattern. It appears we are buying an average of about 11kW a day so 28p times 11 times 365 days means a bill of about £1,200 including vat and daily charge etc (This includes charging the EV but see below). We are trying to improve this without becoming anal about it.   When you consider that our PV system realistically reaches, about 5kW max (due to orientation and roof angle) and about 1kW on a goo
Marvin

Marvin in PV energy use

15

Combo

Running all 4 in the winter is quite interesting:   PV generation: About a week with overcast skies and then a couple of days of sun.   January is supposed to be the low point for PV generation. Based on the EU calculator we should produce about 180kWh in January. We measured 195 which is about 6.3kWh a day on average. However generation happened spasmodically along with the weather.  For example 14kWh on a good day and 0.86kWh on a poor day.   EV Having t
Marvin

Marvin

3

MVHR controls

This is what my system controls would look like if I didn't have a computerised home automation system:       Wait a minute,  I haven't got a computerised home automation system!          
Marvin

Marvin

40

Fitting and running an ASHP

Since January 5th we have used 222kWh on the ASHP over the last 26 days. That's about 9kWh per day for heating and hot water. However some days the hot water temperature has been boosted by the PV excess power going into the immersion heater so let's assume 8kWh per day for 100m2 home. The heating is running 24 hours a day at an average of 20C. The outside temperature has been low (I will look up the records later) with only about 4 nights of frost.   Results from trying different
Marvin

Marvin

4

ASHP Performance

There have been lots of discussions about the effectiveness and efficiency of an ASHP and so I am keeping basic records. I have my own electric meter on the supply to the ASHP so I know how much power has been used whether from the mains or the PV.   The result so far using the ASHP installed is 123 kWhs have been supplied to the ASHP from Jan 1 to Jan the 21st to heat the building and hot water. As it is difficult to split the power used for hot water (and we have an immersion using t
Marvin

Marvin

0

Combo controls

Well the combo is coming together and my wife insists that I make the controls as clear as possible "in case your not here". I wondering what she means.      Still a lot to do though.. 
Marvin

Marvin

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ASHP system tweaking

@Iceverge  recently pointed to@TerryE 's blog "Heating the Slab- an overview" which made me think.   TerryE has a concrete floor that he is using as a giant heat sump, heating up overnight with the warmth slowly emitting from the floor during the day. Such a simple design when the maths is right!    @SteamyTea pointed to a report about boilers and ASHP's which had various recommendations.   Having installed an electric meter for the ASHP the effect of changes can be
Marvin

Marvin

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MVHR Installation 3

Well the ducting is all buried under a foot of insulation in the loft.   The coil boxes have also been covered more since the photo.   Noted the temperatures of the incoming air at the inlets in the ceilings against the outside temperature. Inside 20C ish, outside 7.8C, incoming air 20C ish.  By my calculations this seemed to good to be true and I realised, eventually, that the air was being warmed up as it passed along the ducts inside the thermal envelope of the
Marvin

Marvin

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Heating a building using an ASHP

We don't have a big information system on our ASHP.  I decided just to add electric meters as a way of seeing what is going on. Our home is just about 100m2 floor plan bungalow.    Decided to run the water coils in the MVHR ducts just to draw out any air.  Left them on by mistake until we realised we were too hot but all the radiators were off!  After this I fiddled with the ASHP heating temperature. Decided to set the ASHP heating water temp to 31C last evening for the hell of it. Las
Marvin

Marvin

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ASHP on a flat roof

Not really having much information to go on when installing an ASHP on my flat roof, we decided to go ahead anyway.    Questions that arose were about things like will it blow over, can the warm roof take the weight, can the warm roof take all the vibration,  will it wear away the EDPM, is the condensation OK to go into the soakaway, is there much maintenance required, how heavy is the ASHP,  can we get it up there, can we get the power up there, will the control cables reach where we
Marvin

Marvin

2

Water coil installation into MVHR

This is posted during the design and installation phase during the winter 2021/2022.  The cooling side results are not expected to be known until Summer 2022.   As the air passes through the water coil it changes temperature depending on the coil water temperature. If the coil is going to be used for heating only it can be used without a condensate trap. However as this is going to be used for cooling as well I have constructed a drain in the bottom.   Coil with lid off. Air
Marvin

Marvin

6

Loft insulation

The existing loft insulation irritated the .... out of me. Mainly because I needed to change a lot of pipes in the loft and the roof is only 22.5 degrees and the fluffy was very thick.  What with the 150mm insulated MVHR pipes (190mm thick) 2 high and a roof at 1300 ish it was too cramped. Anyone looking at the ducting photos will see the loft was bare. Before insulating, the bungalow was loosing 87% of the heat through the roof because the rest is so well insulated. Gonna have to tur
Marvin

Marvin

0

Loft insulation

The existing loft insulation irritated the .... out of me. Mainly because I needed to change a lot of pipes in the loft and the roof is only 22.5 degrees and the fluffy was very thick.  What with the 150mm insulated MVHR pipes (190mm thick) 2 high and a roof at 1300 ish it was too cramped. Anyone looking at the ducting photos will see the loft was bare. Before insulating, the bungalow was loosing 87% of the heat through the roof because the rest is so well insulated. Gonna have to tur
Marvin

Marvin

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MVHR Installation 2

More of the same...   When insulating the ducts I noticed that the top of the MVHR was not insulated so I have installed flexi conduit on the cables ready to throw fluffy over the top.       This is the inlet pipe running under the ridge. 150 diameter with insulation held on with cable ties     An installed air damper in red. More about these later....     Water coil with thermal lid. Lid made from PIR.    
Marvin

Marvin

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ASHP installation info

The viewpoint used to decide items is a balance between the outlay cost and the running costs. This system will not be the cheapest way to produce heating and hot water nor the most expensive installation system but a balance related to the existing equipment and personal requirements.   BEST ADVICE: Read the manual of the product you are proposing to use BEFORE you buy, especially regarding the installation and check that it will work for you.   Choosing the ASHP: The s
Marvin

Marvin

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Heating and cooling assumptions.

An Excel spread sheet has been used to calculate the heating and cooling.   One thing also calculated is that at peak energy the bungalow requires as much for the heating in the winter as for the cooling in the summer! So the hottest part of the hottest day and the coldest part of the coldest night need about the same amount of power! This is mainly because of the solar gain through the windows.   The calculations were compared with what has been used for heating and it is re
Marvin

Marvin

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Assessing heating/hot water energy prior to Combo

Following  1 I try to detail the info so people can check...   The bungalow ran on LPG bottled gas for 3 years heating and hot water so I know what was used: I have used the worst 2 years:   I am using the conversion rate of  one kg of LPG gas giving about 14.091kW hours   In 2 years we used about 13277kW of LPG energy for heating and hot water. ( about 10 bottles of 47kg ) If we deduct a modest 2kW for ho
Marvin

Marvin

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List of equipment being installed

The holistic set I am installing is:   ASHP main parts: : Air to water Cool Energy inverTech Air Source Heat Pump CE-iVT9 4.3kW-9.5kW Cool Energy 60L Stainless Buffer Tank CE-B60   MVHR main parts:  Domus HRX2-D Heat recovery System with "summer bypass" 125mm and 150mm rigid circular ducting and Domus duct insulation.     Electricity Generation main parts: PV Sofar Solar Grid Tied Inverter 6KTLM-G2 16 Longi  320W Mono Solar Panels
Marvin

Marvin

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