Monday, 27 May 2019

Open Source Evaporative Cooling controls

Huys decided to Open Source it control diagrams and implementation in order to assist clients in creating sustainable solutions. Main benefits of this approach include:
  1. Controls can easily be scrutinised for design flaws.
  2. Modifications and the impact thereof is simpler to make and understand.
  3. The control model is externally verified to work correctly using symbolic model checking.
  4. Solutions are more sustainable since the client is not locked into the controls vendor anymore.

Wednesday, 3 April 2019

Evaporative cooling in Offices

One of the hidden challenges of Evaporative cooling is dealing with a phenomenon called overcooling during very dry days.

In summer we try to typically introduce air at 18 deg C into a building. This is normally achievable using Two Stage evaporative cooling, but some days, when the air is very dry, you can get excessive cooling when you switch the wetpacks on.

This sudden drop in air temperature can produce supply air temperatures as low as 12 deg C.

The figure above shows that whenever the evaporative cooler goes through a state change, that you risk over cooling.

In offices, this is problematic because the building is typically designed for a constant supply air temperature.

We now have a bypass damper that allows us to smooth overcooling so that after transition, we can mix filtered outside air with over cooled air in order to achieve a constant supply air temperature.

Wednesday, 27 March 2019

Making borehole water useable in Evap Coolers

With current power and water outages nationwide, more and more business have no regular access to municipal water and electricity supplies.

This is forcing people to look at alternatives such as borehole water, which unfortunately typically contains lots of calcium and magnesium ions (hard water).

During evaporation, the ionic concentration of water is increased to the point of deposition and these hard water salt deposits severely limit the lifetime of evaporative coolers, boilers, pipes etc.

We have been developing a water softener to allow clients to use borehole water in their systems:

Our softener:
  • Uses electricity to precipitate ions in the softener, before they end up in your system.
  • Only uses electricity (around 300 Watt) to reduce ionic content to below deposition levels.
  • Uses no salts, resins or any other consumables.
  • Is a sealed, low maintenance stainless steel unit with a long operation time.
  • Is competitively priced to existing softener options.
Initial results are very positive.

Reactor plates

Control unit with power supply and remote access controller

Test reactor 


Deposition of calcite and brucite

Soft mineral deposit being released during regeneration