JohnMo

A quick update 27 October 2023 to today. Including the last cold snap where we had temperatures down to -7, our total electric bill is on average 34.4% cheaper being on E7 compared to standard rate. To make these saving is only possible with the battery, it being charged on cheap rate. Most the period our heat pump was running on WC 24/7. Had a couple of mild days and did night-time floor charging and the saving was 43%, with no day rate electric being used. Comparison includes all heating, DHW heating and all other normal electricity usage. Happy so far

The more I look at it, I would split into two systems. Gas boiler as a backup to the solar for heating domestic hot water and heat star unit. Leave the ASHP to do the pool and UFH all year round. Go directly from ASHP to pool HE, and use close coupled tees from the supply line to the UFH pumps and mixers - the flow would come off this line and the return would also go the same line. No need for the NRG unit. Follow the layout as attached CCT WORCESTER BOSCH.pdf

A decent gas boiler comes with WC and load compensation and both can be selected to work together, great for radiators. Put controller in the hall or a place you want as a reference temp, lob in an approx curve, set target temp and you are done. Zero Reason this approach should not work on a heat pump. Controller just trims back or adds temperature to the output flow to match temperature required.

Outdoor temp sensors are supposed to remain away from the sun. You could extend the cable and place the sensor away from the unit and sun. But not sure if the sensor is used as part of the defrost detection, so it knows when to initiate?

They use them offshore in two variation, but most are use for making hypochlorite (strong bleach) - hydrogen is vented as a waste by product. Never very reliable. Simple process but the controllers are almost an after thought and generally rubbish.

Looking at gas boiler WC curves they start at 20 degs with an outside temp of 20 degs. So it should be really as simple as take note of outside temp set flow temperature at a reasonable guess, say 35 degs, how much hotter or colder than target temp is the house after 24 hrs, set appropriate curve by reading the supplied chart. All Atag boilers come with WC, they have a simple selection chart, low temp radiator or high radiators or UFH, well insulated etc. and points you towards a starting curve. You can then adjust the whole curve up or down on the controller like you would a thermostat. Should all be pretty basic stuff for an installer.

Looks ok, I also looked at the NRG manifold, look interesting. Check that antifreeze valves are the best solution.

That ties in well with what I heard last year, onshore wind turbines (allowed in Scotland) with hydrogen plant in the base, lorry comes around to collect it on regular basis. The tech issue is storage without great expense.

Think you miss the point of WC, there is zero complexity you have a controller (either come with the boiler or cheap enough as an option) and within it a simple outside temp - flow temp curve. That's it, no thermostats, or radiator valves - a fully open system. You calculate the curve based on house heat losses, you balance the system, job done. People make a WC system complex by adding thermostats and make lots of justification of why their system needs it. Biggest issue is installer training or lack of, S and Y plan rules the roost, because its easy for the installer.

Why bother?

No - the heat pump reads resistance of a probe directly and then generates a temperature from that generally. So the resistance is the important bit

Most the road transport is completed by another company, one of wife's relatives works as a driver, they have hydrogen and electric lorries on order apparently - on the order of the distillery companies.

It's the way thing are going, Scotland has already pre-sold lots of 'green' hydrogen to the Netherlands for one. Think we can already produce over 100% of the grid requirements on a windy day and more so overnight. So why not? Easy to implement, uses spinning reserves needs very little storage space per kWh. If a turbine is being turned off because it's energy isn't needed, make stored energy.

That's not really an issue, I have a direct readout on the probe in the cylinder plus I have a further 4 gauges on the cylinder so I know where the thermocline is located. My heat pump has a simple external on unit controller and no readout in the house.

Solved. Thanks to an unrelated post by @ProDave Basically the heat pump using a NTC-10kΏ probe is just looking for a resistance, above a given resistance DHW starts below a given resistance it stops. So the default settings are 44 degs heating starts, 48 degs heating stops. So long as the heat pump sees resistances in the range it expects it is sorted. So solution is two resistors in parallel, the second brought into and out of circuit by a simple normally closed relay. Two resistors one 5.6kΏ always in circuit and a 15kΏ resistor switched in/out by the relay. 5.6kΏ probe is equal to 41 degs 5.6kΏ and 15kΏ in parallel is 4.1kΏ is equal to 51 degs. So relay in a deactivated stated would have the resistors in circuit, powering the relay opens it's contacts and removes the second (15k resistor) from the circuit. So now I can simulate a probe but use use wireless switching. Will cost more in postage than parts

That info is great it solves an issue I have with my heat pump, at moment my call for DHW is an on off contact, but really want to use that contacts for some else. And use the correct temperature probe connection to call for heat. So I can use a variation of the above.

You use a high output temp ASHP to heat the cylinder to 70, but why would you, when you can heat to 45 - 50.

Floors should never get hot. Your mixer always mixes return water with new hot water. So if you have the supply water to the mixer at 45 the mixer is unlikely to give much above 35 to the floor. For a given flow temperature increasing a loop flow rate will increase the heat output to the room, reducing flow rate heats the floor less.

1. No issue with the way setup, you are able to change pump without having to bleed full UFH system. 2. Are you hearing gurgling when UFH is on? Are the flow rates being seen what you expect? 3. What temp is the heat source flowing at i.e. boiler?

Nip back up to a previous comment Make it a second thought to drive the thermostat ever upwards. Price it so it more expensive, give them a free option to greater efficiency, a warmer house and 20% energy cost reduction. Environment wins, their energy costs go back to where they previously were before they added costs to gas prices.

So thermal store or UVC we will assume heating by immersion. So the same as far as heat input. Thermal store contains a heating medium, the UVC is wholesome water. Thermal store, hot water is produced via a heat exchanger. Heat exchangers require a dT between hot and cold side to function and are sized for a given dT. Once the dT lowers the heat transfer falls off rapidly. So if you require 45 deg water, your cylinder could be at 70 deg, and once it has been depleted to 50 the heat transfer has diminished enough so you no longer get 45 deg water. An UVC contains water only heated to 45, nearly the full cylinder contents can be used as hot water as a thermocline is formed, cold below and hot above, warm at the thermocline. So UVC, can be heated less, has less standing losses, can utilise more of the hot water heated. If you have the skills to install a thermal store do the UVC course, cert is valid for 10 years and training is one day at your local college. That's what I did. So self install and self service. Thermal store are not a future proof install and they are not that good with a heat pump, although some do use. There are two of us and we are using a 210 heat pump cylinder heated to 49 degs. Takes 45 mins from the heat pump. I would also consider a heat pump, simple single zone, 3 way valve and heat pump cylinder, just do a self install. Bargain come up the time on eBay etc.

Easy to set up badly just like an ASHP. To set up well is the same as a heat pump. All boilers should be WC and not on an S or Y plan. They should be getting seasonally efficiency of over 100%, the energy saving would be staggering from 80 to over 100% in millions of homes. No insulation to do, keep the same radiators, customer just keeps money in the pocket.

You need insulation to stop noise transfer. Otherwise every step upstairs will be amplified. It's also a requirement of building regs. UFH in bedrooms is rubbish. We have it and it's never the correct temperature as the response time is so long. Either nothing and electric points for electric heaters (if required later) or radiators. That would be my advise.

I would say to get a high SCoP install is quite straightforward. You eliminate any input from 3rd party controls. You run 1 or 2 zone maximum, but zone volumes must be larger than the minimum acceptable for the heat pump, otherwise a single zone. Heating system isn't hydraulically separated from heat pump. Radiator systems are allowed to run load compensation as well, in houses where solar gain is an issue. The system is correctly balanced and has the correct WC curve installed, prior to installer being given the grant money. All setting are behind an installer password. 3rd party verification, can remotely look at house temperature, input and outputs to confirm install is acceptable (grant money release tick box by 3rd party). Home owner can close the remote access after 31 days via a simple switch. I would think all the above should come into play if you want a grant, if you don't have the grant do what you want, it's your money.

Interesting.