A Wind driven Heating system in Cornwall with EMMA at the Helm

Setting the scene

In 2011 a call came to the office from a man undecided about what turbine he would put up and also how he would use this turbine to heat his old renovated house in Cornwall. As it goes the gent in question was at the beginning of a renewable journey and the choice of turbine was his main priority at that point in time. True to his word over a year later the date for pouring the base for the turbine was set and he wanted an EMMA fitting. By this point in time he had commissioned an engineer to build a complex heating control system leveraging various fuels in priority from Carbon free down to oil as the last resort.

Three phase EMMA TP45: 3kW’s per phase.

The install was going to have a 3 phase output with a max output of 15kW. A TP45 with a 9kW output was recommended from the beginning of the project. While there was excess energy available the client was advised that he could upgrade at a later stage at very little cost once he was more familiar with the amount of output he would get from the turbine.

Similar to many sites where EMMA is fitted with wind turbines the fit of power to heat was going to be perfect. Cornwall has an abundance of good laminar wind due to its proximity to the sea. During the winter the turbine would produce most of its power. With the wind sucking the warm air out of the house the Wind Turbine would have the power to replenish this but only with EMMA TP45 steering the right amount of power into the heating system. The turbine would produce the most power when it would be needed most.

On this particular site an EMMA with EC was not required as the DNO had permitted the full export capability of the turbine. With EMMA in place the power that would have been exported to the grid is instead put to good use on site. The client still receives his full FIT for every kWh produced and will get his deemed export.

System design

Cool Power Products worked with the client and his installer to advise what the EMMA could do for him and how it could integrate with his heating system. The solution from a Cool Power Products perspective just to put the EMMA power into his custom built Akvatherm 2500L tank. While the tank and heating system look like they could be parts from a spaceship the functionality for EMMA in this case was quite straight forward. Three immersions into the tank at the bottom to keep the stats from tripping out was the simple and best solution.

There was one EMMA for each 3kW immersion where the EMMA would only put the exportable power into the tank. The cold water is normally at the bottom of the tank which allows the immersion to stay online for longer thus putting more power into the tank.

The client had the safety of the EMMA high temperature cut off but he also had the over temperature cut off on the stats which is a requirement if the tank got too hot. As an absolute safety measure a thermal release valve was also fitted failsafe which would release excessive hot water allowing cooler water to in to cool the tank down.

The tank served as the main source of heat to supply the house heating the radiators but also the hot water through an indirect cylinder in the house just as if it were a standard oil heating system.

The heating control system

The heating control system that was implemented on the site carries out a number of functions:

  1. It monitors for a house call for heat from the house.
  2. It monitors the tank temperature.
  3. It makes logical decisions on what to do based on the tank temperature and on calls for heat from the house.
  4. Its goal is to use the tank when it gets a call for heat and the tank temperature is above 55’C.
  5. If the buffer tank is above 70’C it engages the house circulating pump and heats the DHWC and the rads to keep the buffer tank in a safe temperature range.
  6. If the tank is below 55’C the control system will switch over the flow and return valve to the oil boiler so the oil boiler is used to heat the house only.
  7. In the house there is log burner with a back boiler. If this is on it will supply the central heating once it reaches an acceptable temperature.
  8. If the boiler has provides sufficient heat to the house the excess heats the buffer tank to be used at a later stage.

The EMMA installation

Andy Whitty Electrical carried out the install with the clients help as they would be doing the wiring for the turbine. While untrained by Cool Power Products the electricians were able to follow the Cool Power Products installation guidelines with phone support at any point it was required. The installation was carried out with the promise that a CPP representative would call to the site to check the install. The install was up and running perfectly when two of the CPP called in while on their way to give a training course in St Agnes. One change was advised which was to stagger the EMMA’s to avoid a triple heating of air getting to the top unit which could lead to the unit operating outside its ambient temperature range.

A little on the plant room

The turbine outputs wild three phase power that is fed to the three aurora rectifiers which can be seen under the three aurora inverters.

The 3 Aurora Inverters on the wall are single phase inverters which are fed variable DC power from the three rectifiers underneath.

Each inverter feeds a single phase. Depending on the install the Aurora has the ability to read the frequency of the turbines RPM’s through a link from the rectifier and load the turbine with a frequency curve. Alternatively and most common a voltage curve is used. The inverter uses a known output voltages vs power curve generated from a number of pre-programmed points to load the turbine.

The correct power curve is crucial to the harnessing of the available power from the turbine and also to load the turbine properly so it operates as per its design specification. The two large 1:1 transformers at the bottom of the picture are used to provide galvanic isolation to the inverters to prevent trip faults.

Each EMMA is monitoring one phase. A CT will monitor the output of one inverter to one phase and another CT will monitor the demand on that phase. This is triplicate across the three phases and the three EMMA units will balance the power independently.

Upgrade to a larger EMMA, its easy and cheaper than you think!

The wind turbine proved to output a lot of power from time to time and by monitoring the information display on the EMMA the client could see that he still had an abundance of power on two of his three phases that was flowing to the grid even with 9kW per hour going to his tank. Wanting to use as much as he could to heat the tank the client ordered an upgrade of two of the three EMMA units. The beauty of EMMA is that it is easily upgradable and uses all the initial hardware. The client purchased two 3kW add ons for his units to bring his EMMAs up to 15kW of power diversion capability. The units stayed in on the wall with just two control wires to be hooked up from the EMMA’s to his 3kW SSR add ons and a simple menu change.

Solution consultancy for extra heatingwith Willis Flasks

Figure 4. Cool Power Products Willis Flask add on  solution design.

As the tank was so big and there was only one immersion port left the client was a little unsure of how to get the extra heat into the tank. He posed this question to Cool Power Products where he was advised to use a Willis flask solution across the feed and output of the tank. This was a neat fit as the client had a number of shut off valves that allowed him to fit the Willis flasks without draining the tank.

The Willis flask is a copper flask that encapsulates a 3kW immersion with a flow and return pipe connection on it.

They are generally used when replacing an immersion is too difficult or draining a tank is not an option. The flask system uses the siphon effect to heat the water by the cooler water at the bottom of the tank heating in the flask and rising to the top of the tank creating a cycle.

The flask solution requires some modifications to help it run properly and to get the most out of the renewable generation.

Cool Power Products were able to advise on how to do this properly using stats and a pump to keep the hot water flowing out of the flasks before they would trip out their stats.

Further Upgrades

The client has already upgraded to a small cascaded system to harness more of his existing power. As already mentioned the EMMA is built with easy upgradability in mind. If the client wanted to add in a 10kW PV array for instance the upgrade would be quite straight forward and would use all his existing equipment. The addition of our voltage detection and failsafe isolation system coupled with a change to the software is all that would be required.

 

 

Summary

A common theme of the EMMA case studies is how the system is used for heat with wind, whether it is in a house or even is a Dairy setting. A little known fact about EMMA is that it has been developed to match wind turbine output and has been used to replace other cheaper systems that don’t have the ability to track the rapid ups and downs of a wind turbine. EMMA keeps your wind turbine online, heating your house and tracking power properly.

Turbine: CF Green Energy

DNO: Western Power but with a sufficient export limit for the turbine.

Installer: Mick Vincent the owner and Andy Whitty Electrical

EMMA Type: TP45 for the initial install (3 x PWM). Supplied by www.coolpowerproducts.com Upgraded to a TP45/75 (2 extra SSR’s)

Customer: Mick Vincent who is very warm and very happy with his EMMA and Cool Power Products experienceJ

 

Comment from the Owner

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 I have worked out that every hour on the Akvaterm (supplied by EMMA) is a saving of 2 litres of oil, which at today's price is £1.12, total so far of £3313quote_mark.gif

The above is over a 2 year period .

Testimonial:

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The EMMA's have performed better than expected doing their job seamlessly. I have to say that working with Coolpower has been like working with a partner rather than just a supplier, they have been there whenever I've had questions and ideas. I wouldn't hesitate recommending them to my friends and neighbours. quote_mark.gifMick Vincent.

 

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