Geothermal, heat pumps and beer!

Causeway Energies is on a mission to decarbonise heating and cooling at larger scale in industry, commerce, public services and heat networks.  At the core of our offer is geothermal energy and storage, heat pumps and energy efficiency.  Our technology is evolving rapidlly to allow us to offer higher temperature heat including lower pressure steam.  We’re not in the game of decarbonising heat with temperatures higher than 200 ºC, but we are able to service a lot of sectors, which constitutes more than 40% of the challenge.

One of the sectors we are focused on is Agriculture, Food and Beverage.  So, in this blog, to illustrate the potential for geothermal heat in the sector, we have the pleasure of talking about three of our favourite topics: geothermal, heat pumps and beer!

The beer making process and energy

A big brewery, manufacturing beer at an industrial scale, is a very energy intensive process, a fair amount of electrical power demand and even more heating and cooling.  For heating the biggest breweries can as much as 10 MWth of heat and even more for cooling and chilling.

Where does this heat get used?  All through the process from the malting process to making the mash boiling in the kettle to boiling the wort and finally in pasturisation of the beer product before dispatch.

It’s important to note that most of that heat is applied at temperatures of 50 ºC (120 ºF) to 75 ºC (195 ºF).  Only the boiling of the wort and the later higher temperature stages of kilning get closer to and over 100 ºC (212 ºF).

In terms of energy use it’s actually Cleaning In Place (CIP) of vessels and pipes between brews that accounts for the majority of demand.  In one brewery we have assessed CIP made up half of the hot load.  Higher temperature work (>100 ºC and above) was only 12% of that heat load.

The cold thermal load in breweries is typically about the same, or even higher that the hot side load.  Cooling is involved in bringing the temperature of the liquid from the kettle so that is ready for fermentation.  Fermentation temperature also has to be controlled as fermentation is exothermic.  Finally, some beers like lager enjoy a cold storage period to complete the beer.

Efficiency opportunities

We find with our lot of our clients and target sectors that cooling is considered to be an electrical problem (refrigeration), while heating is a combustion problem (gas boiler or combined heat and power turbine).  We see them as the same integrated energy problem.

With thermal loads as described above, the problems can be combined into one with electrification of the heat using heat pumps.  In this way the heat extracted during cooling is recycled instead of being wasted to air through chilling units.  The recovered heat from cooling is circulated back into the heating system as part of the thermal energy load utilized by the heat pumps in delivering the heat load.

There are other efficiency opportunities and novel techniques available to save energy.  For example, for the highest temperature demands – boiling – we can arrange the heat pump system such as the heat pump discharge heat exchanger is integrated into the kettle.

Industrial Heat Pumps

There is a great new range of high temperature heat pumps coming to the market with European and Asian manufacturers leading the charge.  These heat pumps are able to deliver output temperatures of up to 165 ºC (330 ºF) currently and so cover off the higher range of thermal demand in our brewing process.

The new Industrial Heat Pumps (IHPs) come in a range of sizes – a lot in the range 100 to 300 KW_th but also several big badass heat pumps with 10+ MW_th outputs.  The efficiency of these new machines is encouraging with Coefficients of Performance (COP) in the range of 2.5 to 3.5.  This means for every unit of electricity used to drive the heat pump, 2.5 to 3.5 units of the heat are delivered as supply to the process.  Currently that extra heat is being sourced from waste heat from a fossil fuel originated heat stream, so while they are lowering the emissions of the facility by using more of the heat generated by combustion there are very few if any examples yet where low/zero carbon heat as being used as the source.  This is where geothermal comes in.

Geothermal heat and storage

Geothermal energy is already used round the world in direct use applications – more than half is transferred to thermal comfort and water heating by geothermal (or ground source) heat pumps.  We in Causeway Energies believe that both shallow and deep geothermal resources can be utlised much much more to decarbonise industrial scale demand.

Recent engagements with clients have taught us that it is critical to integration with other clean tech to deliver the best outcome.  For example, integration solar thermal heat with geothermal storage enables the balancing of variable and intermittent solar while recharging the of the geothermal resource.

While Causeway is currently focused on the design and build of projects using proven applications, we are also working in the background on the technology of higher temperature heating using geothermal energy as the source.  Achieving this breakthrough, will double the market and decarbonisation challenge that is addressable with our technology.  For this example, brewing, we can already take care of 85% of the heating and cooling needs.  The novel technology will soon allow us to service all of the beer-making process.

Sláinte!