Help with project

[andyriches]

Would I be able to run the below
Sorry if it’s a silly question

I can get my hands on some 12v 160 APH batteries

I was hoping to run an air source pool heat pump from these

If I had 4 batteries in parallel that gives me 12v 640 APH
The kit says it’s 900 w so around 4amps
If I have an inverter will this run my air source heat pump ?
And then would I be able to charge the batteries with solar panels
Use the stores energy early hours and then charge the barriers during the day ?

 

[Hedges]

May be possibly, not necessarily very practical or cost effective.
In particular, PV and batteries for space heating is likely not a good fit.

I can get my hands on some 12v 160 APH batteries

I was hoping to run an air source pool heat pump from these

If I had 4 batteries in parallel that gives me 12v 640 APH

12V x 640 Ah = 7680 Wh
Lead-acid batteries are typically run down to about 50% DoD (100% would quickly kill them)
3840 Wh usable

48V x 160 Ah is same total.

There are 24V an 48V inverters available as well. Some low-cost ones such as MPP out of China.

The kit says it’s 900 w so around 4amps

900W/220V ~= 4A
You're in UK, so 220V

If I have an inverter will this run my air source heat pump ?

Yes, if not too large.
Starting the compressor probably takes 5x the wattage as running, 900W x 5 = 4500W surge required.
Good 2500W inverters could do that (surge 2x), light weight ones might need to be rated at least 4500W.

And then would I be able to charge the batteries with solar panels
Use the stores energy early hours and then charge the barriers during the day ?

3840 Wh / 900W = 4 hours run time

Lead-acid batteries can usually charge at around 0.12 to 0.25C, so with enough panels could recharge the 50% usage in 2 or 4 hours, followed by 2 hours absorption.

It may work, maybe not the most practical. Deeply cycled lead-acid batteries, assuming designed for that, typically last 200 to 700 cycles so maybe 2 years daily use. Longer if seasonal.

If you have to buy new replacements, probably will cost $0.50/kWh of cycle life. Add to that cost of equipment including PV panels. Compare to your utility rates.

"heat pump" - powering an AC from PV is reasonable because lots of sun in the summer (maybe not as much in UK.)
Using it for heat in the winter, much less sun. Check an insolation website to estimate effective sun hours.

 

[andyriches]

Thanks for the reply
Would looking at evacuated tubes be better than ?
The kids pool isn't massive, I already had the air source heat pump but with the prices of elec just now it would be really expensive, hence why i was asking about solar

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[Hedges]

I'm interested in evacuated tubes. Good at making heat well above ambient.
In the US, mostly flat panel collectors used for swimming pools.
Could be great for domestic heat in winter. Need to protect manifold from freezing. For pool, maybe no heat pipe, just pump pool water through configured as drainback.

Solar thermal may still capture more energy per square meter than PV, but PV is above 20% now. Used panels are cheap ($0.10 to $0.50/W)
Year round and amortized over 20 years, PV panels alone are $0.0025 to $0.0125 per kWh. So even seasonal and over fewer years, very cost competitive.

How efficient are heat pumps? 200% or 300%?
Resistance heating is of course 100%, but simple, dumb, cheap.

PV direct to resistance elements works. Make a resistance that will operate around Vmp, Imp of array by series/parallel connection of elements, and selection of element wattage/voltage.

Main issues would be that electromechanical switches (thermostat, over temperature valve) are for AC, won't work for DC. You can use them at 24VDC for pilot duty switching a DC rated contactor.

In a tank-type water heater, safety shutdowns and temperature/pressure relief valve are important.
An open pool, no issues with over pressure. Could get too hot, but not likely with loss to air. Have to ponder any possible shock hazards, but if heater is in a metal manifold that grounded and has water pumped through, think that can be made safe. Loss of water would burn out element, so some configuration that holds a captive volume and won't siphon dry.

 

[Ampster]

Would looking at evacuated tubes be better than ?

Those are designed for high temperature differentials. Pools have low temperature differentials and the typical plastic thermal panels are ideal for pool heating from solar.

 

[andyriches]

Those are designed for high temperature differentials. Pools have low temperature differentials and the typical plastic thermal panels are ideal for pool heating from solar.

Would them tubes above not work then ? i can get them for £300,by the looks of it you just pump from one end and the other would go into the kids pool, the pool is only 3mx2m

 

[42OhmsPA]

See if you can find something like this.

Solar System to Run Electric Pool Heater Off Grid

Late to the party... Pool guy in my past life... Listen to others and use solar to water heat.. Enersol was the brand we used. https://enersol.com/enersol-resources/parts/ Countless installs in the Northeast where we removed NG / propane heaters and extended swimming season by 3 months on...

diysolarforum.com

 

[Ampster]

Would them tubes above not work then ? i can get them for £300,by the looks of it you just pump from one end and the other would go into the kids pool, the pool is only 3mx2m

A friend uses them for a hot tub but that temperature rise is a lot more that needed for a kids pool. I don't know what the options are in your neck of the woods. Perhaps that is the most cost effective.

 

[andyriches]

Hi all
i can get the following for £600
Would this work ?

1kw complete solar system suitable for a shed/ outbuilding/ garage/portable set up. The system consists of 4x250w panels 1x EPEver 2.4kwh continuous discharge hybrid none grid tied inverter.
The batteries i have are 195APH and i have 4 of them.
That's the inverter below.

EPEVER UP3000-M6322 24v 2400w inverter charger - Sunstore Solar

EPEVER UP3000-M6322 24v 2400w inverter charger The UPower series is a new type of the inverter/charger combining with solar & utility charging and AC output.

www.sunstore.co.uk

The person selling the system said the below

It plugs into a standard 13a socket, the solar panels and a 24v battery. You can put a 2.4kw load on it. My hot tub was 1800w. It will run the device via the solar first, if there’s no solar it will use the battery, and if the battery is depleted then it would use the 13a supply. This can be changed in settings to a different priority. Keep in mind the maximum it can ever provide is 1kw via the solar as that’s the size of the array. Our hot tub heater would cycle in and out for a maximum of about 3-4kw a day during the summer which this system managed without issue.

I wouldn't want it running from a 13a supply and he said that can be changed in the settings.

If this ran his hot tub I'm sure it can run my heat pump?
Th heat pump details are below