Greenhouses Meet Aquaculture – Aquaponics Boom
Good swimming water for walleyes thanks to geothermal energy from greenhouses
Greenhouses do not have to be heated in the summer. In fact, there is often even a surplus of heat, especially if geothermal energy is being used. With that surplus it is possible to heat the water for indoor fish farming. The Greenhouse Horticulture Business Unit of Wageningen University & Research is investigating – together with European partners – whether geothermal sources can be utilized better through combinations of greenhouses and fish farming (so-called aquaponics).
A constant water temperature is required for fish farming all year round. Supply and demand are less constant in greenhouse horticulture: relatively much is heated in winter, and there is a surplus in summer. In addition, there are more and more cultivation companies with a geothermal source. This creates an even greater surplus in the summer. Selling that heat could provide a different business case for geothermal sources.
Recirculating aquaculture system
That is why the greenhouses of the WUR in Bleiswijk now have an advanced fish farming system, a so-called recirculating aquaculture system (RAS). The largest tanks contain around 10,000 liters of water. Several thousand fish live in it. Walleye, to be precise. This species is very suitable for consumption and is becoming increasingly popular, both among consumers and growers. If the heat from the greenhouse can be used for indoor fish farming, then that probably also has a positive effect on the business case of aquaponics.
WUR investigates the effects for about a year. How much heat can be exchanged, and how much heat is saved with it? For this, the researchers simulate the residual heat from the greenhouse (of approximately 35°C) and from a geothermal source (approximately 80°C).
WUR carries out this research in collaboration with partners from Iceland and Slovenia. The heat requirement for algae production and food processing processes is also being investigated to investigate the potential of circular food systems for the use of geothermal energy. Funding for the research comes from the European GEOTHERMICA – ERA NET Cofund Geothermal.
Toyesi works with some great suppliers of heat exchangers. SWEP plate heat exchangers are one such product that we can assist farmers in Australia set up a similar solution.
This project design by Florian Ablinger utilises heat exchangers. Heat exhangers are an excellent way to transfer heat from one water source to another body of water.
However, this transfer is never perfect. Usually the best you can get is about 50% of the temperature difference transferred.
So if the water off the LED lighting say is 42 degrees C (107F), only a portion of this heat will be lost to the cooling water, so the circulating water may heat up to around 30C. Which will also have the benefit of allowing the LED lights to run cooler, increasing their potential lifespan.
The 30C water will mix in the storage tank and the pass into the heat exchanger. If the circulating water in the 2nd loop is say 20C, you will have a temp difference of 10C thus you would potentially transfer 5C across to the 2nd loop for passing around 25C.
This is great for a Hydroponic set up or light temp control in hydronic heating of a green house.
However swapping out the heat exchanger for a Toyesi Water to Water Heat Pump, you now have the ability to boost the secondary water to 45 Degrees or more depending on your requirement.
A much more suitable solution for hydronic space heating of a greenhouse.
Toyesi – Water to Water Heat Pumps.
Just one of Toyesi’s many energy capture, storage& recycle concepts.
IF you want to now how Toyesi and its Horticulture Affiliates can help you and your horticulture, Hydroponic or Aquaponic business increase energy efficiency, reduce running costs or minimise your waste energy then give us a call.
Contact us on 02 9679 9400 or by email firstname.lastname@example.org and we can discuss how we can best assist you in your projects.