Why Saudi should opt for water cooled instead of air cooled heat rejection solutions
An occupant of a factory, hospital or large residential development in Saudi may not feel the cost of the energy needed to keep him cool on a hot weather day.
But you can bet owners and Saudi officials do, especially that the kingdom is pushing for legislation to remove energy subsidies in 2018 and introduce utility prices more in line with actual costs.
Georges Hoeterickx, Director Business Development, EVAPCO Europe, BVBA, will have a very important talk at the January HVAC-R in Jeddah, 2018, about how chillers with cooling towers can reduce the installation and operating cost of your cooling plant.
Chillers and cooling towers are tasked with removing heat and rejecting it to the air.
The question is whether the process of removing this heat is done by an air cooled or water cooled systems, and there lies the opportunity and challenge for Saudi, which opts in many instances for air cooled solutions when it makes more economic sense to go with water cooled options.
“There is a particular case with Riyadh to prove that water cooled solutions reduce energy cost, and connected power and first cost to a large extend” said Georges.
“It’s the most extreme case when you compare water and air cooling having the dry bulb temperature for air cooled at around 49 degrees oC and requiring sizeable more condensing temperatures than water cooled based on a wet bulb temperature of 22 °C, thus big losses on cost and energy.”
The numbers talk
In his presentation, Georges will make comparative measurements in both Riyadh and Jeddah for both air cooled and water cooled systems.
Air cooled solutions, using chillers with capacity range up to 400 tons/chiller, cooling capacity lowers from 400 to 350 tons, while efficiency loss goes from 0 to -37% when ambient temperatures increase from 30°C to 48°C.
For water cooled solutions, using open or closed type cooling towers, and chiller capacities ranging from 100-5000ton/chiller, means for Jeddah a 15 degrees oC lower condensing temperature can be achieved while for Riyadh even a 25°C lower condensing temperature compared to air cooled solutions can be achieved.
A lower condensing temperature amounts to less work for the compressors, longer lifetime and less energy consumption.
In terms of connected power, air cooled solutions for 400-800 ton capacity in Jeddah require 552 and 1104 kw electrical input, while in Riyadh this requires 635 to 1270kw.
In terms of first costs, Jeddah’s are $175,000 to $350,000 respectively, and Riyadh are $235,000 to $470,000 respectively.
In terms of connected power, water cooled solutions for 400-2500 ton capacity in Jeddah require 349 and 1735 kw electrical input, while in Riyadh this requires 295 to 1682kw.
This means for Jeddah 35% less connected power at 400 tons up to -47% at 2500 tons, and for Riyadh a -54% at 400 tons, up to -56% at 2500 tons.
In terms of first costs, Jeddah’s for water cooled solutions are $218,000 to $844,000 respectively, and Riyadh are $203,000 to $647,000 respectively, which is a +18% first cost for 400tons in Jeddah but becomes a -20% savings as we go to higher to 2500 tons, and a -35% initial cost savings at 400 tons and goes to -50% savings at 2500 tons.
“Installer ’ costs and labor are almost the same or if a slightly higher and more complex for water cooled solutions requiring more time to install, but the differences between air and water cooled are so huge in terms of energy and first costs savings that they would be easily absorbed to validate the switch,” said Georges.
“I advise new construction to adopt water cooled solutions in Saudi, while those owning air cooled equipment could make the when they replace the equipment, though we have equipment being switched earlier to capitalise on savings immediately.”
Georges advocates clear regulatory frameworks for the industry in Saudi.
He said Kuwait mandates a threshold of 500 tons capacity to install water cooled, while other GCC countries like the UAE, or Oman, there is a strong drive it to go on water cooled solutions, above certain capacities, to reduce energy cost, power consumption and connected power.
“There are opportunities when using water cooled solutions,” said Georges.
“We will continue doing good technology awareness in the kingdom , George concludes.