D
davelondon
Guest
My parents live in the UK, which is usually a pleasant temperature. However recent heat-waves in the summer (40C / 104F) have meant we're thinking about adding air conditioning. They're currently spending a large slice of their monthly budget on heating in the winter, so we'd like to do this without adding to their electric bill in the summer. Also, in the winter we'd like to use the system in heating mode to reduce the heating bill.
I've been doing lots of research into a similar system for a truck based camper, but it's possible I'm ignoring cheaper / better solutions. Perhaps you can take a look at my ideas / the components and give me your thoughts?
They have a studio outbuilding, about 6m x 4m with a roof that is always in the sun. It's built recently with good insulation, so we're thinking about a small 12,000 BTU system in this space. I think we can fit about 12 x 400w panels on the roof.
I like the idea of a 48V native aircon system, so we don't need an inverter. I was planning on using the Hotspot Energy system in the truck, but there's now a similar Chinese system which is re-sold by many alibaba merchants for less than a quarter of the price. I've been chatting with Solar Green who seem to be very knowledgable about the system and quoted me $418 for the air conditioner plus $780 for shipping to the UK (including import tax).
We'd like to use the system in the evenings after the sun goes down, so a battery backup is essential. I have 16 x 280Ah EVE LiFePO4 cells which I'm happy to donate to the project. I was planning on using these cells in the truck project with an Overkill Solar BMS, and that seems like a good choice here too.
Assuming 12 of these 425W panels, arranged in two strings of 3S2P, we could use two Victron 150/45 MPPT controllers (about £350 each). Perhaps there are cheaper options?
We'll install the system in the studio, and monitor it for a year. If it works well and there's an excess of power generated, we'll think about adding another similar aircon unit (or maybe two) to the main house.
Questions:
I've been doing lots of research into a similar system for a truck based camper, but it's possible I'm ignoring cheaper / better solutions. Perhaps you can take a look at my ideas / the components and give me your thoughts?
They have a studio outbuilding, about 6m x 4m with a roof that is always in the sun. It's built recently with good insulation, so we're thinking about a small 12,000 BTU system in this space. I think we can fit about 12 x 400w panels on the roof.
I like the idea of a 48V native aircon system, so we don't need an inverter. I was planning on using the Hotspot Energy system in the truck, but there's now a similar Chinese system which is re-sold by many alibaba merchants for less than a quarter of the price. I've been chatting with Solar Green who seem to be very knowledgable about the system and quoted me $418 for the air conditioner plus $780 for shipping to the UK (including import tax).
We'd like to use the system in the evenings after the sun goes down, so a battery backup is essential. I have 16 x 280Ah EVE LiFePO4 cells which I'm happy to donate to the project. I was planning on using these cells in the truck project with an Overkill Solar BMS, and that seems like a good choice here too.
Assuming 12 of these 425W panels, arranged in two strings of 3S2P, we could use two Victron 150/45 MPPT controllers (about £350 each). Perhaps there are cheaper options?
We'll install the system in the studio, and monitor it for a year. If it works well and there's an excess of power generated, we'll think about adding another similar aircon unit (or maybe two) to the main house.
| Panels | £2,145.60 | 12 x 425W Trina Vertex S Mono |
| Brackets / installation | £500.00 | ??? |
| MPPT controllers | £700.00 | 2 x Victron MPPT 150/45 |
| Cells | £0.00 | 16 x EVE 280Ah LiFePO4 (already have these) |
| BMS | £167.33 | Overkill Solar BMS |
| Aircon | £351.12 | Super Green Solar TKFR-35GW/DC-H with R410a |
| Aircon delivery and import tax | £655.20 | |
| Cables / fuses | £200.00 | ??? |
| Total | £4,719.25 |
Questions:
- Is these a better / cheaper way do do this?
- Am I mad going for a 48V DC aircon system?
- Am I mad going for a direct-from-China aircon system with no reviews?
- What's the easiest / cheapest way to mount the panels on the roof? We'll be doing this DIY to save cash. The roof is a normal flat-roof construction (plywood with a bitumen waterproof membrane) at a 7 degree angle.
- Any better / cheaper MPPT controllers?
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