DIY Heat Bank
DHW secondary components assembled ready to install (remotely from cylinder). A service isolation valve and in-line 'Y' strainer are visible in the mains water inlet (bottom right) which are not shown in the diagram. The electrical connections to the pump and flow switch, and the triac electronics are not shown in this photograph.
- Direct HW cylinder (a standard Indirect cylinder could be used, either with extra tappings via e.g. Essex flanges, or Tee-ing the connections from the boiler into the top and (existing) bottom connections of the cylinder.)
- Pump (standard 15/50 CH circulator type)
- Plate Heat Exchanger (PHE)
- Thermostatic Mixing Valve (TMV) 22mm
- Flow switch wired to switch on pump when flow is detected
GEA-Ecoflex Unit 8, Waterside Business Park Redwall Close Dinnington-Sheffield S25 3QA Tel.: +44-(0)1909 551 107 Fax: +44-(0)1909 550 885 e-mail: email@example.com
Copper brazed plate heat exchanger model:- BP12M-20-G1G1
Compact gasket-free Brazed Plate Heat Exchanger consisting of corrugated pressed stainles steel plates (1.4401), which are brazed together with copper in a special vacuum process. Designed, produced and tested in sites with quality systems in accordance with DIN ISO 9002 requirements. Pressure-Vessel Approval according TÜV and EC Pressure-Equipment-Directive (CE).
|Specification for 1 x M12-20-GG|
|Operational data:||Side A||Side B|
|Heat transfer area:||0.22||m²|
Note this is probably under-sized for this application: 100kW would be preferable.
Farnell order code 730890 Manufacturer Part Number FS22 FLOW SWITCH, 22MM 3.75 L/MIN; Switch Poi £11.60 + VAT & p&p
This is a reed-switch whose contacts are rated 15VA, max 1A AC, into resistive loads.
The pump is rated 82W, 0.36A @ 230V AC and is an inductive load so the circuit shown is used to drive it.
|Part||Suitable Component||Suppliers order code (CPC)|
|Flow Switch||Also available from CPC||SN35601|
|The Metal Oxide Varistor (MOV)||Epcos B722 Series||RE03667|
(shown on the motor)
|can either be assembled from basic components, or a module such as the Ampohm FE-SP-HDR-23-100/100 could be used.||FT00715|
- Discussion of design of circuit from sci.electronics.design
An alternative requiring no electronics would be to use a flow switch capable of switching the pump directly. These ara available from DPS.