Random Renewables Thread

For anyone who has any form of heat recovery ventilation, I'm curious as to what happens if the house gets overheated in winter?

Say you're cooking Christmas dinner for a bunch of people. I've noticed that something like a kitchen/dining room will get pretty warm with a bunch of cooking appliances going full blast, not to mention a bunch of guests trying to work their way through the wine cellar

I guess the ventilation will try to distribute the heat to other rooms which are cooler, but will it eventually start bypassing the heat recovery and letting some cold air in?

Or will it just try to keep as much heat in the house as possible and wait for it to eventually dissipate after all the guests have passed out from a combination of turkey, wine and heat?

That's bad. I wouldn't let that rest. Contact ESB networks and demand a massive payout based on all your time of charging the car and other stuff at "night" rate when you were charged full day rates. Shouldn't be that hard to do some sums in Excel. It won't go anywhere of course, but if you end up in the small claims court you can be almost guaranteed that you will win the case (provided the sum owed to you is not more than €2500)

Some lucky souls in the UK are getting a 1 year trial to test a new V2H charger before it goes to market. Would have loved to try that over here myself. They get it at a savage discount and get to keep it afterwards. Only Nissans for now, 'compatible CHAdeMO-based electric vehicle: Nissan LEAF (model year 2013 onwards), Nissan e-NV200'. Goes up to speeds of 6kw in and out.

Vehicle To Home | Vehicle-to-Home (V2H) Bidirectional Chargers | INDRA

Sure, cons are there's wear and tear on the battery. And car has to be in the driveway. But pros is it's largest house battery you'd ever have. And batteries are paid for to be used (whether in a car or house).

If V2H became a runner, could even get a written off EV (that battery was good / safe in) and land it in a shed somewhere connected to a V2H charger. Then run forever more on night rate & solar :)

BTW many of us use a DIY powerwall in a very similar way. Unfortunately, V2H is not really where we need to go, we need to go V2G. Basically buy electricity when it is cheap and green off peak (or make your own) and sell it back to the grid at peak times when it's really expensive (and dirty to produce from fossil fuels)

A Leaf sold on DD at the weekend for €4k, not a bad option at all if you could get the V2H hardware (worth about the same) installed for free for some sort of trial though 😂

Excellent. I realised a long time ago that the standard advice to heat up your entire cylinder to 60C at least once a week was way OTT.

His added strong points are that there are rarely / never victims in domestic houses, quite likely there is legionalla, but simply not enough of it to make you sick. And that there is more risk from scalding from hot water than from getting sick from legionella

After watching that video, I'll never ever worry about legionella again or do any extra heating up because of it. We have a super high turnover of our cylinder although it's big. And the only time we would be absent from the house for a few weeks would be the summer, upon our return the entire cylinder is always at the max of 60C because our solar thermal setup so not a single little monster would still be alive 😁

Yeah, that one about turning off when leaving the house verses leaving on 24x7 has been banging about for years. Comes up a lot on the channels. It's not "a depends" really, you should knock it off IMHO

The reason is pretty straightforward if you think about "your house as a system". We know that no matter what you do (insulate etc) ....you will have energy losses from your house. If you didn't then if you heated it to 21C it would remain forever at 21C even though you turned off your heating system.

If you take a ridiculous example of extrapolating it out and go on holliers in January for 2 weeks. Naturally you wouldn't leave on the heating as you'd be paying for those loses even though there's no one in the house. Stands to reason then that there is some "tipping point" shorter than 2 weeks where it might be favorable to leave on, verses turning it off and back on again. So, what would that time be then, if it was better in fact.

With normal losses the time that it takes my living room to cool down is about 2 hrs (depends of course on how cold it is outside etc) but generally speaking. So after 2 hrs the energy I've put into the room at zero hour is mostly gone. So, if you're leaving the house for more than 2 hrs, then you'd be putting energy into the room which is otherwise not used (by you) in feeling warm, i.e. wasting energy. If you left the house for less that that, then there might be an argument as you have to heat up piping etc.

Course heat pumps change the landscape as they don't work the same way as boilers (above). They tend to move the temp slowly, but even then, I'd turn it off if leaving for work and probably turn back on via remote control/timer 2 hrs before coming home.

Part of the argument in video was if people are in the house at random times (like you there), then a more constant temp if better. And that 'set back' outside the main hours saves costs of course.

Can you link to that video? I was looking through the channel history but couldn't spot it

Sounds similar to my house, take a nicely insulated and airtight house and then drill a big hole through every wall to let the cold breeze in

I'm considering an MHRV for similar reasons, want to improve air quality and stop the cold draughts

I'm hoping it'll add a bit of sound insulation as well as I get the noise of planes flying over quite a lot during the night

https://youtu.be/kGs_biFA87Q

Yeah that's it exactly. Very new and well insulated house... then some annoying draughts. :( Also have some noise but it's mostly cars, or even if someone is standing on the road outside talking you can hear it very clear (depending on the room).

I currently have a wired EPH 3-zone system with upstairs, downstairs, and water. It has the motorised valves on the tank and heating loops also. How would this work?

Most rads have TRV's except for hallway and bathrooms. I leave the bathrooms valves either off entirely or on very low level. I need to get the hallway changed to a TRV either way.

Forget it. Bottled gas is ludicrously expensive. If you have a modern house with HP heating, you don't need to use fossil fuels, maximise PV first, maybe go bigger battery second. But the latter ONLY if you DIY and get the parts for reasonable prices. I don't get all those people coming out of the woodwork in the last year or so, now we have FIT, that spend a fortune on a battery that will never pay for itself

Yeah I've found exactly one pellet system so far that generates 700W from a Stirling engine for 9kW of heat. Currently my heat pump outputs 6kW so it's already oversized for what I would need

If I did go for a system like that then I would probably have it heating a large buffer tank to store the heat for use throughout the day. A bit like the water battery you've been using

I am starting to wonder if I'm thinking the wrong way about this. If I heat the house with something other than electricity then that removes a big chunk of the demand from my solar panels. So perhaps CHP is the wrong thing to be looking at...

what temperature difference does that stirling engine need to run?

@the_amazing_raisin what do you heat the house with now and what size is it? You said 'If I heat the house with something other than electricity then that removes a big chunk of the demand from my solar panels'

Asking as I've a plug-in rad on a thermostat in the kitchen / siting room at the moment. It's heating that 30sqm room for only 2kWh a day. Meaning electricity isn't breaking the bank. Granted it gets the sun and heat from the kitchen so starts as a warmish room. And the weather isn't cold now. Perfect for this time of autumn and same for start of spring. Haven't turned GCH on so far.

It's on 24hrs a day for last 2 weeks as I'm seeing if that helps (kinda opposite of what makes sense, that having on low heat all the time means the heat moves into the walls as thermal mass). Set to 17c at night. Then I change up to 20c during the day, bit by bit (I'm wfh so am here). Comes on every 2 hours at night for maybe 15mins. And unlike the GCH it keeps the room at a constant temp. Different strokers, different folks - our clan are grand with the rooms we sit in being warm and hall and upstairs cold.

We've no insulation downstairs and single pane windows. So we lose heat quickly normally. I know we need to sort that, but waiting on the money tree to regrow :)

Also bought a door hinge spring a few weeks back and makes a huge difference. In winter if the sitting room door is open, the heating would run all day and not stop. So now I don't need to nag the kids to 'close the door' :) MARIE Hydraulic Spring Door Closer with Hold Open Soft Close Size 2 with Automatic Adjustable Arm Operated for Commercial & Home 25-45KG Weight Door with Installation Video EN1154 Certification Black : Amazon.co.uk: DIY & Tools

Here's the thermostat plug that comes on + off at temp you set (for plug-in rad): KETOTEK Digital Thermostat Plug Socket Temperature Controller 220V with Sensor Probe, Thermostatic Plug Heating Cooling for Greenhouse Freezer Refrigerator Fermentation : Amazon.co.uk: Business, Industry & Science. In time I might move that to a wireless temp sensor in HA, but not a rabbit hole I need to go down now as works.

Could put a plug-in rad in to 'boost' the room you're in for a few hours in depths of winter - if it won't confuse the temp sensor in the heat pump so it turns off. Then heatpump is perfect apart from that. Gotta love Irish high tech ventilation - hole in the wall :)

If you get the head down on the solar install and get that booked in, then you're done for now

Solar farms 'can benefit wildlife'. Link: Solar farms a 'blight on the landscape'? Research shows they can benefit wildlife (theconversation.com)

Saw a good pic the other day of sheep sitting under the panels to avoid the heat of the sun :) I'm a city-slicker but assume it's possible to share the land (like they are doing in places with fruit trees and crops in the same field to give multiple yields on same land). And farmers then get the rent on the space for the panels (if they get into a lease). Ok, makes it more tricky with machinery and expensive panels in terms of risk of damage to them. But getting 2 incomes from a single field.

🤣 We know without optimisers a tiny % of shading on one panel has a huge drop in output for the whole string. Imagine what cow pats would do? :)

32 counties at this stage I'd reckon. Athlone was always the centre point in my view.

sounds good !

The 3 gorges dam hydro plant in China is 10 times as powerful as that 😁