Sunamp Stack

[Stones]

Prior to deciding upon the SunampPV as my preferred means of providing DHW, I investigated the Sunamp Stack.  

 

http://sunamp.co.uk/...SunampStack.pdf

The main attraction of this unit is the ability to store up to 60 kWh of useable heat energy. For low energy houses, this meets and probably vastly exceeds the total DHW and heating energy requirements.

The following info is a summary of the information provided by Andrew @ Sunamp.

The unit is currently progressing through testing, but should become available this year, 2016.

As yet Sunamp do not have any heat loss data for the unit, but given that the casing will be made of the same vacuum panels as the Sunamp PV is made from, I think we can expect low losses (certainly lower than a suitably sized thermal store). 

The storage medium with the unit are the same PCM cells as the Sunamp PV. These are designed to have a 20 year lifespan, warranty for 10 years. 

Each PCM cell stores between 2.2 and 2.5kWh. Eventual output depends on unit configuration.

The Sunamp Stack is a storage unit only. It would need to be paired with a heat source - electric flow boiler, high temp ASHP, although they are working on incorporating the charging system used in the SunampPV.

Preferred output temp set for DHW to give maximum flexibility. This would mean blending down for UFH applications.

The unit can be configured in several different ways, with full size units measuring approx 550mm x 550mm x 2100mm (16 cells) or 800mm x 550mm x 1600mm (18 cells). One interesting thread of our discussion was the option / possibility of buying a full sized housing, racking system and internal hydraulics, but only installing a limited number of cells, which could be added to later if total demand exceeded what was planned (for whatever reason). 

A full size unit would allow households to use E7 as their energy source. A smaller sized unit (i.e. limited number of cells) could be run off an E10 tariff, although E10 is somewhat more restrictive in that there are only a few energy suppliers which support that tariff.

Cost wise, Andrew suggested a full size unit would be in the region of £5.5K to £6.5K. If someone wanted a smaller unit, he indicated that the casing/ racking/hydraulics would be £1K-£1.5K, and £250 - £300 per cell. As a tailored/bespoke item rather than a large production run item, individual units would be priced according to individual requirements. 

Installer training would be facilitated by Sunamp.

 

Although designed to be used with a high temp ASHP, I think it has a lot of potential using direct electric (off peak) as the energy source in a low energy / passive type build.