1. © 2013 Farm Energy Centre PE 013 Refrigerant based dehumidification

2. © 2013 Farm Energy Centre They’re just a decent size refrigeration unit How do they work? Warm, wet air 20 o C 85% RH 15g/m 3 of water Cold air 16 o C 100% RH 14g/m 3 of water Warm dry air 30 o C 45% RH 14g/m 3 of water EvaporatorCondenser Water Compressor

3. © 2013 Farm Energy Centre The energy balance Warm, wet air Cold, wet air Warm dry air EvaporatorCondenser Water Compressor 1kWh 3kWh 4kWh

4. © 2013 Farm Energy Centre Simple energy costs But there’s more…. Cost of electricity Cost of heat (CoP of 4.0) Equivalent cost of gas (85% efficient boiler) 9 p/kWh2.3 p/kWh1.9p/kWh (56p/Therm) 6p/kWh1.5p/kWh1.3p/kWh (37p/Therm)

5. © 2013 Farm Energy Centre A bit more physics What happens when the vents are open? – Lose the energy in the water vapour (latent heat) – Lose the energy in 20 o C air that is replaced with say 10 o C air (specific heat) – This adds 1 to the CoP New CoP is 5.0 Cost of electricity Cost of heat (CoP of 5.0) Equivalent cost of gas (85% efficient boiler) 9 p/kWh1.8 p/kWh1.5p/kWh (45p/Therm) 6p/kWh1.2p/kWh1.0p/kWh (30p/Therm)

6. © 2013 Farm Energy Centre The project at Red Roofs Nursery 4 dehumidifiers in 6,000m 2 Each unit – Consumes 10kW electricity – Removes 45 litres/hr of water

7. © 2013 Farm Energy Centre Energy facts/figures 2013

8. © 2013 Farm Energy Centre Energy facts/figures 2014

9. © 2013 Farm Energy Centre Energy facts/figures Total heat use - 2013

10. © 2013 Farm Energy Centre Energy facts/figures Total heat use - 2014

11. © 2013 Farm Energy Centre Energy facts/figures Heat saved

12. © 2013 Farm Energy Centre Energy facts/figures Electricity used

13. © 2013 Farm Energy Centre Crop data 2013

14. © 2013 Farm Energy Centre Dehumidifier Control

15. © 2013 Farm Energy Centre

18. Crop data 2014

19. © 2013 Farm Energy Centre Dehumidifier Control

20. © 2013 Farm Energy Centre

23. Financials Check out the spreadsheet