Heat pump / inverter DIY

richardc1983

I dont know how you would go on with the power but split type a/c uses 230V as standard.

Think of an extension lead, the indoor units run off of the outdoor unit, in my case I have 2 (can connect upto 4)

The indoor units connect to the outdoor unit like an extension lead connects, except theres no plugs there is pipes that connect to it. So the extension leads provide the power to the indoor units also.

There are extra connections on the outdoor unit which enable you to connect more than 1 unit. However this limits certain things. You have to have all the units in heating or cooling mode. For instance if you want downstairs in heating but upstairs in cooling its not possible. Now I have never ever needed to have them in different operations so its not a prob and I dont think you would either. SteveX on the forum also has a/c installed however has goine for 2 separate systems, works the same however has individual outdoor units for the indoor units. So he has 2 indoor units each individually connected to 2 outdoor units, meaning he can have different operation modes if he wishes. ALso the other benefit of having separate systems I guess is that if one breaks down u still have the other as backup.

Either way its cheaper to install a multisplit as your only needing 1 bigger outdoor unit.

I had quotes for both and its less work to install 1 outdoor unit than 2 so its cheaper.

Hermann

Jayen4 wrote: »

There we go...that's the beast ! Needs work,but I'll get there. (Sorry about the big pic).

I think the Rover may struggle when towing uphill. :eek:

In fact I think it may struggle going on the flat or even downhill (might need to uprate the brakes!).

Hermann

Jayen4 wrote: »

The trailer will be 'mostly' staionary,but will be travelling around some of the time.

Can you give some idea of what power will be available to you.

ie Are going to be on a mains electric hook up? Everywhere you go? Sometimes? never?

Using a Generator, Solar PV, Batteries etc etc.

These factors significantly influence the form heating you should be using.

Jayen4

Hermann wrote: »

Can you give some idea of what power will be available to you.

ie Are going to be on a mains electric hook up? Everywhere you go? Sometimes? never?

Using a Generator, Solar PV, Batteries etc etc.

These factors significantly influence the form heating you should be using.

Firstly,thanks Richard for the explanation. I understand now. Just one thing. Would you mind telling me how much your system cost,please ??

Herman :
Very funy re the Rover ! lol ... I think a tractor unit with 350hp + would be more the required means of motive power.

The general idea with the power requirements is that I'm trying to make the trailer a 'stand alone' set up,so that I don't have to stop at certain places,just to get the 'hook up' facilities. Most caravan or RV parks power supply is questionable anyway !
I was speaking to someone on E-Bay (who was selling ex server back up inverters) and he said that I could run a twin inverter/battery bank set up,whereby one set could be used to charge up the battery bank of the other set.....thereby creating a 'perpetual' system,not needing a generator or solar panels at all ! However,I think that I would have a back up generator,for high power draw needs and 'emergencies'.
The aim of using such a system,means that I would have conventional 240 volt power at all times,giving me the abilty to use normal household appliances and equipment.
That's where I'm trying to get to anyway.....

Hermann

Heat pumps may well have a part to play in your set up but I doubt you'll get enough power to simply provide a replacement mains and then just plug all your usual stuff plus a heat pump or two.

Minimising all you power requirements is absolutely essential. For heating this means insulation, more insulation and then some insulation not forgetting draughtproofing. The less heat you lose the less you need to put in in the first place!

For batteries you'll need an expensive, heavy setup. Ordinary automotive/liesure batteries just don't cut in this sort of application. They'll quickly fail due to the constant discharge/charge cycles. Think forklift batteries (a bank of 2v cells) to get a reliable setup, these could easily set you back thousands to buy new and be heavy to drag round.

Twin battery banks tend to be frowned on by those living 'off grid' as far as I'm aware, they seem to prefer concentrating on getting one decent bank that meets their needs.

You've then got to charge them. PV panels and controller perhaps for when its sunny, decent genny to top up when needed maybe even a wind turbine.

There's plenty of communities online for those 'off grid' as I expect you've found so pick their brains about what works and what doesn't, some of them have spent 10's of thousands only to find it doesn't work well enough and then start again!

Some forums that may be worth asking on include Navitrons .....
http://www.navitron.org.uk/forum/index.php

Also worth a look are the canal boat forums, they live off grid and have to be energy efficient, use alternative heating etc. so some of it may transfer to your needs .....
http://www.canalworld.net/forums/

Good Luck with the project, looks great fun.

richardc1983

Excellent post Hermann!

richardc1983

Jayen4 wrote: »

Firstly,thanks Richard for the explanation. I understand now. Just one thing. Would you mind telling me how much your system cost,please ??

The equipment cost: £2650 & then installation on top is approx £400 for the day, this depends on how easy it is to install though, could be more could be less you would need to get quotation. My system is a commercial system but I got it for a lot less as a friend who is in the trade got the equipment at cost price and installed it for me.

One point to make as well, if your going to be running on a generator, the "fixed speed" systems I mention, have high start up currents/amps. For instance they will draw as much power as when you switch a kettle on and need to be wired into the consumer unit with its own switch whereas the "inverter" systems start up very slowly and have the same effect as a dimmer switch beiing turned on, they soft start so as not to draw large ammounts of current.

Point to consider as generators like soft start equipment and do not like appliances that have large drain on them.

stubedoo

hi all

i have read with interest all this good news about ASHP

my house is old and poorly insulated

but i am not after a hot house just a reasonable background temp

obviously will improve insulation but no cavity walls and very limited loft insulation opportunities

is ASHP any good for me ?

cheers

Jayen4

Thank you Herman and Richard. I hear what you say.....all very useful information. Much appreciated !

Andy_WSM

Just thought I'd add to this thread as I have found it very interesting.

I am in the SW UK and have a whole house ducted Fujitsu inverter A/C system which I use to heat & cool the house. The "house" is actually a 2 bed bungalow, so the ducting & "IDU" was easy to fit in loft. The pipework and "IDU" are all insulated and I have the benefit that I can mix in some fresh air if I want too.
We have had nights here when the temperature has dropped to -7C and the A/C has continued to work well. I do monitor the energy usage and am using about £25 a week to run it, which is far less than my gas used to cost. I should get smarter and use the built in timer, but am comfortable with both the bills and the temperature in the house!
The unit is on 24/7 with the main control panel being in the hallway and set to 21C. If I want warmer it takes only minutes for the unit to ramp up.

The disadvantage I guess is that all rooms in the bungalow are heated and cooled the same, but as I use all rooms it isn't a problem.

One advantage is that if you have a "hot spot" i.e. kitchen, laundry room, then the excess heat (that you might have let escape through an open window before) is picked up by the A/C and redistributed through the whole house.
Further advantages: No space consuming wall mounted radiators, no cold spots / damp. No condensation (the unit will also dehumidify), No noise, it is virtually silent in operation when it is just ticking along.

As for split units - I have a log cabin in the garden which is my home office. I have a split unit in there which is used for both heating and cooling. First thing in the morning the cabin was cold & damp, by mid day roasting hot, so I fitted a split unit which is left set to heating @ 16C overnight which keeps off the cold & damp and set to cooling @ 22C when it gets too warm. This unit is only costing about £3 a week to run and the office is usable in all weathers comfortably now - and no more damp paperwork!

Hope this post helps someone make a decision.