Chillers are devices that use a refrigerant to cool down a fluid, usually water or water/glycol mixture, and circulate it through a heat exchanger to provide cooling for buildings, industrial processes, or other applications. Chillers consume a significant amount of energy and contribute to greenhouse gas emissions. Therefore, improving their efficiency and performance is a key challenge for the HVAC industry.
One possible way to enhance chiller efficiency is to use a nanofluid additive, which is a liquid containing tiny particles of a solid material, such as metal oxides, that can alter the thermal properties of the base fluid. A nanofluid additive can increase the thermal conductivity, heat capacity, and viscosity of the fluid, which can improve the heat transfer between the fluid and the refrigerant, and reduce the pumping power required to circulate the fluid.
A recent trial conducted by HT Materials Science (HTMS), a sustainable materials technology company based in Ireland and Italy, demonstrated the potential benefits of using a nanofluid additive in chillers. HTMS tested its heat transfer fluid, Maxwell, which is a drop-in, nanofluid additive comprised of submicron aluminum oxide particles suspended in water or water/glycol, with Tabreed, a district cooling company that operates 89 plants in the GCC region.
The trial was carried out at a Tabreed district cooling plant in Khalifah City, Abu Dhabi, that supplies chilled water to a 55,742 m 2 educational campus. The results showed that adding Maxwell to the chillers increased their efficiency by 13.6%, leading to an overall plant efficiency improvement of 9.0%, compared with the same period in 2022. This translates to a significant reduction in energy consumption and greenhouse gas emissions. Applied across Tabreed’s current portfolio of district cooling plants, the nanofluid additive could prevent approximately 200,000 metric tons of greenhouse gas emissions annually and save 335 million kWh of electricity.
The table below summarizes the main parameters and outcomes of the trial:
| Parameter | Value |
|---|---|
| Plant capacity | 15,000 RT |
| Chiller type | Centrifugal |
| Chiller capacity | 2,500 RT |
| Nanofluid additive | Maxwell |
| Nanoparticle material | Aluminum oxide |
| Nanoparticle size | 50 nm |
| Nanoparticle concentration | 0.1% by volume |
| Chiller efficiency improvement | 13.6% |
| Plant efficiency improvement | 9.0% |
| Energy saving | 335 million kWh/year |
| Emission reduction | 200,000 metric tons/year |
The trial also confirmed that the nanofluid additive did not cause any adverse effects on the chiller components, such as corrosion, fouling, or clogging. The nanofluid additive was compatible with the existing chiller system and did not require any modifications or additional equipment. The nanofluid additive was also stable and did not settle or agglomerate over time.
Following the promising pilot study results, Tabreed and HTMS are in discussions to introduce the Maxwell technology to other district cooling facilities in the company’s portfolio.
Nanofluid additive is a novel and innovative solution that can help the HVAC industry achieve higher efficiency, lower energy consumption, and reduced environmental impact. By using nanotechnology, the nanofluid additive can enhance the performance of chillers and other heat transfer systems, and provide significant economic and environmental benefits.
