So now I have a solar PV system how do I make the most of it???

zeupater

grahamc2003 wrote: »

.... Last summer when it was really hot outside, we happened to venture into Debenhams, where they had probably 20 large mobile air conditioners going full blast. Just heated the shop even more (it was unbearable), since none of the hoses were connected (and indeed couldn't be since they were situated near the middle of the sales areas), so the hot exhaust air was going straight back into the shop....

Hi

The majority of these portable units used by stores are evaporative air coolers which don't pump heat and simply exchange heat reduction for increased humidity .... as long as the humidity isn't allowed to condense within the building, the cooler air will cool the thermal mass before the humid air is extracted and replaced via the building's mechanical ventilation system ....

.... doesn't stop the staff allowing the units to run dry and just act as fans though ...

HTH
Z

EricMears

Cardew wrote: »

Note the statement 'so I have started to relax about using the tumble dryer especially over the wetter weather'

I wonder how many people - especially with Rent a Roof systems(and little electrical knowledge) are like this poster?

Alas, quite a few - probably conned into it by the favourite sales hype of "our panels even generate when it's cloudy".

But you don't actually need to be an electrical engineering wizard to be able to read what the system is actually generating, what you're using and hence what you could really afford to switch on.

Cardew

EricMears wrote: »

Alas, quite a few - probably conned into it by the favourite sales hype of "our panels even generate when it's cloudy".

But you don't actually need to be an electrical engineering wizard to be able to read what the system is actually generating, what you're using and hence what you could really afford to switch on.

I would think quite a few with a Rent A Roof installation have absolutely no idea of what the generation meter is or where it is located(in attic?) - especially as they don't claim the FIT.

grahamc2003

zeupater wrote: »

Hi

The majority of these portable units used by stores are evaporative air coolers which don't pump heat and simply exchange heat reduction for increased humidity .... as long as the humidity isn't allowed to condense within the building, the cooler air will cool the thermal mass before the humid air is extracted and replaced via the building's mechanical ventilation system ....

.... doesn't stop the staff allowing the units to run dry and just act as fans though ...

HTH
Z

Yeah, I know what evaporative coolers are - these weren't. They were probably 2 or 3kW each stand alone/mobile industrial units hired during the hot weather. There was cold air coming out the front, and hot air out the back through an unconnected vent. There wasn't even the possibility of venting them to the outside.

I spoke to someone who seemed to be in some sort of charge, and before I spoke he said 'I know what you are going to say' - and he did (which surprised me no end). He said he had no choice but to run them - a dictat from higher above, even though he knew they were 2/3kW (each) heaters and not coolers. They simply had to be seen to be doing something because so many customers had complained about the heat (before the units were installed). All very strange.

John_Pierpoint

orrery wrote: »

Just a cautionary note:
I've taken delivery of a 110V site transformer today, with a view to running an immersion heater through it.

A quick first test reveals that the no-load current is already over 1 amp! So, just over 250VA without connecting anything else to it (although it only shows as about 50W). :mad:

It will be interesting to see what the figures are when connected to my 3kW immersion!

If it not too personal a question, what is the specification for the transformer, where did you get it and how much did it cost?

Thinking this sounded like a good idea, I got as far as finding these details of transformers, and thought that the cost versus the cost of night time electricity, while bearing in mind the possibility of export metering, would make the exercise poor value against Economy 7 on dull/winter days.? :

http://www.screwfix.com/p/continuous-portable-transformer-with-output-sockets-3kva/23676

grahamc2003 wrote: »

On a related point, I had a salesman/engineer (who was also the knowledgeable company MD) round to quote for solar thermal yesterday. (there's a new 'Thermodynamic' system for thermal which is basically a small heatpump and a radiative 'panel' to gather the heat, meaning for 350w they claim2.2kW of heating and temperatures of 55C). Anyhow, we chatted about the looming RHI, and the reason it almost certainly won't be metered for domestic is due to the experience so far from metered commercial systems, where the heating is set to full and windows opened wide in order to 'farm' the rhi. If you go in a shop, and it's much too hot, you know the likely reson. Don't you just love 'green' subsidies!

In case you missed it, here is the proposal for domestic RHI - compliance to be back dated !!

I bet there is a an Energy Performance Certificate hurdle to be overcome.

I am toying with installing insulated "shutters" to try to trap more of the day time solar gains. [Have you noticed the number of people who now have double curtains and even blinds with "Velcro" to hold them against the frame of the window ?]

EricMears wrote: »

Alas, quite a few - probably conned into it by the favourite sales hype of "our panels even generate when it's cloudy".

But you don't actually need to be an electrical engineering wizard to be able to read what the system is actually generating, what you're using and hence what you could really afford to switch on.

A generation meter next to the importing meter - both with the one-flash-per-watt red LED does it for me. Every meter cupboard should be so kitted out:D

Brian99_2

My 110v transformer was £60 from Screwfix. 1.5 KVA.

It does get hot, with 30watts wasted. It is switched on and off using my relay system when the solar generation gets to about 500 watts.

My modest solar panels are 1.4 kW.

Works fine.... although some would want to put ALL the spare power into the immersion heater/aquarium/jacuzzi.... I am happy to see some go to the neighbours.

sly_dog_jonah

Brian99 wrote: »

Works fine.... although some would want to put ALL the spare power into the immersion heater/aquarium/jacuzzi.... I am happy to see some go to the neighbours.

I'm happy to export power once our own household energy needs are satisfied, but until our hot water tank is up to temperature I'd rather export nothing rather than having to use gas (or imported electricity) to do so at other times.

With our immerSUN we can put the washing machine and/or dishwasher on and not worry about whether the immersion load is resulting in import, because the power to the immersion is constantly adjusted to ensure that power isn't imported (and if power is ever imported due to household load, the immersion is switched off).

orrery

John_Pierpoint wrote: »

If it not too personal a question, what is the specification for the transformer, where did you get it and how much did it cost?

I got mine from ebay - 3kW intermittent duty, 'Defender' branded. £60 delivered. Screwfix have the identical thing "Portable Transformer with 2 Output Sockets 3kVA" for £57.10.

However, this power rating isn't necessary as a 3kW immersion will only be about 750W at 110V.

I'm using mine to power a 500W (or 125W at 110V) radiator in the study, so this would have been a better match for me:
http://www.tlc-direct.co.uk/Products/SC5300.html
... no cheaper, but it looks to be based on a toroidal transformer so probably more efficient.

Martyn1981

orrery wrote: »

I'm using mine to power a 500W (or 125W at 110V) radiator in the study, so this would have been a better match for me:

I'm trying a similar thing, but without the transformer. Got an oil filled rad around Xmas time. It has 400W, 600W or 1100W (both on (must be some roundings)) settings.

Just about to start using it again. I've only used it as 400W, and after about 20mins it gets hot and so runs approx 10 mins on and 10 mins off, so approx 200W/hr.

Obviously it can't compete with GCH, but it worked really well last Jan/Feb onwards on warmer days, just to maintain a room's comfort level, rather than put the heating on. I tried to use it when generation was approx 600W+, but to be honest, it did such a good job, that I'd guess it was better than GCH, since, even with TRV's and several turned off (frost settings) it's probably less energy in total.

Will 'eventually' warm a room to 19C, but better to use after house heating goes off, just to maintain 19C or so and to work in conjunction with daytime solar gain.

Downside, only really able to use when Wifey is out, and in combination with ski socks and a fleece top, but seems a waste to heat whole house all day, when the GCH will warm our house in 20 mins or so, so better to switch it on as the sun starts to wane and Wifey is due home.

In fact, worked so well, I'm thinking of getting a second, and running them both through really cheap mechanical plug in timers with 30 min on, then off (with the two operating on different 30 min cycles).

No intention of using at the same time as GCH, and obviously on really cold days, they are of no use. Ideal use - think, 'oh, it's a bit chilly, but I don't really want to put the heating on'.

Mart.

[Deleted User]

In an effort to further reduce the electricity bill I'm thinking of using PV to heat the 210lt water tank. DHW at the moment is heated by ASHP. Tank has a 3kw element. During late spring/summer/early autum I just can't get daily useage below 9 units. Looking into the immersun as i don't really want DIY it. Obviously during these months most leccy is being exported.

Any thoughts or experiences?