EMMA 3G and 42kW solar PV

Hot water, wood drying, quad bikes… our most fascinating project yet.

Our largest system to date was installed this November on an Organic Dairy Farm near Appleby, Cumbria.

Three EMMAs and 42kW of solar PV

The system consists of 42kW of solar PV on the roof of a cattle shed that was built to spec to hold the weight of the array.

42kW of solar PV, managed by an EMMA 3G Cascade GVS system

This three-phase system uses 3 Fronius Inverters one on each phase feeding back to the grid. (EMMA three phase systems are normal single phase systems multiplied by three.)

Love Solar were the installers who took this progressive step with Cool Power Products to design and install our largest system yet. The farmer had a uniquely efficient setup on site for water heating that has been significantly improved by installing EMMA Cascade GVS.

Dairy heater

The three EMMAs (centre of photo), mid-installation.

On one phase is the Dairy heater which is used on a daily basis to washout all the Milking equipment with superheated water:

  • This water begins its life being fed into a buffer cylinder that is heated to 45°C by a heat exchanger used for cooling the milk.
  • This warm water is then fed to a second tank with three immersions making up to 9 kw/h of heat. that are supplied by EMMA and 2 cascaded SSRs. This second tank however is only fed with water from the buffer cylinder during a set period each day when a timed valve is opened to let the warmed water in (e.g. after wash down in the morning). At this point EMMA uses the power created by the PV array on that phase to heat the water to a specified temperature to kill all bacteria during the washdown.
  • During the night time hours the Timer function on EMMA is used to heat the tank to the specified temperature using the Economy 7 rate electricity. This is the most cost effective and efficient way we have seen to heat water.
To estimate  the hot water requirements for your own farm/dairy, please see this simple Excel spreadsheet calculation: Dairy hot water wash down requirements .


Buffer Tank

The three EMMAs photographed as the system nears completion.

On another Phase there is approximately 3000 litres of a buffer tank to heat the house and also the hot water:

  • This is heated by a Wood Log boiler but also has 4 x 3Kw immersions on the tank that are controlled by a second EMMA GVS cascade system with 2 SSRs.
  • The system can heat the tanks water using the electricity created from the PV panels and significantly reduce the amount of wood burned to heat the house as well as free up some time for the owner from frequent reloads of the Wood Log boiler.
  • In a similar fashion the EMMA unit can make use of its timer function to heat his boiler during the cheaper night time tarriff when there is no sun for the PV.

Wood Drying Shed & Quad Bikes

On the final phase there is a wood drying shed where all the wood is stored to dry out for use in the wood log boiler mentioned previously:

  • The EMMA on the this last phase is designed to drive 4 x 3kW air heaters using EMMA Cascade GVS with 3 SSRs.
  • It is quite possible in a final twist to this extremely environmentally friendly install that one of these cascaded SSRs will be changed and used as a charger for an electric quad bike.

EMMA Keeps Grid Voltage Steady

The Fronius inverters used in the EMMA system.

Because of the size of the install the Grid Voltage Stabilization (GVS) mechanism built in to each EMMA unit through its AC transducer will keep the grid voltage steady on site and help eliminate overvoltage outages of the inverters thus boosting the output of an install this size.

This install is on the Electricity North West Network.

Our Biggest Project So Far…

This has been the most fascinating install that Cool Power Products have ever been involved in. So far it is the biggest three phase system we have designed and shipped, but possibly not for long, given the level of interest in EMMA GVS.

Find out more about EMMA Models .

ELITE Control

The ELITE is the latest addition to the EMMA product family. While we consider it to be the Elite of power diversion and monitoring it is in fact EMMA's little sibling or as we call it EMMA lite.


EMMA Cascade

The modular heating system that can grow and grow


EMMA with Export Control

EMMA with EC allows for installs to have a greater renewable output than the Max Export Capacity (MEC) on site by diverting excess energy to heat.