CHILLERS | ENERGY USE IN THE MIDDLE EAST ADDING SALT TO THE MIX When comparing the energy use of air-chilled and water-cooled chillers, power used in desalination plants must be taken into account in places such as the Middle East, say Mott MacDonalds Jismi Mohammed and Fergus Donaghy Type of project Electricity Residential customers: villa expats 26.8 ls.kWh-1 average daily consumption up to 200kWh Commercial customers 20.0 ls.kWh-1 all consumption W ith the impacts of global warming, the depletion of freshwater resources is accelerating. In Middle Eastern countries, with low rainfall, natural freshwater resources are limited, and desalination of seawater is the primary source of potable water.1 However, desalination consumes energy, so any process that uses potable water generated from desalination will have a high level of embodied energy. The term water-energy nexus defines this scenario. Global building standards, such as ASHRAE 90.1/189.1, and region-specific standards, such as the Dubai Green Building Regulations, consider water-cooled chiller systems as the baseline for energy performance analysis/ audits. Water-cooled chillers use cooling towers in which water is evaporated to provide cooling. Even though a water-cooled chiller consumes less electric power to deliver Water 30.5 ls.kWh-1 average daily consumption more than 200kWh 7.84 AED/1,000 litres average daily consumption up to 5,000 litres 10.41 AED/1,000 litres average daily consumption more than 5,000 litres 7.84AED/1,000 litres all consumption Table 1: Water and electricity tariffs 2017, Abu Dhabi Distribution Company2 (Conversion: 1 AED = 100 ls = around 0.22) A changing landscape on chiller solutions is inevitable in the Middle East the same cooling compared with an air-cooled chiller, it is important that the in-built energy expenditure of desalinated water used in chilled water production is accounted for in the comparison of chiller energy usage. Desalinated water In Dubai, approximately 90% of potable water produced is desalinated, and this is representative of other Middle East regions. Desalination, storage and distribution of potable water is energy intensive. Each cubic metre of potable water supplied in Abu Dhabi costs 10.41 United Arab Emirates Dirham (AED)2 (2.35). This corresponds to around 34kWh of electricity, based on the Abu Dhabi municipality rate of 30.5 fils per unit (0.07 per kWh) of electricity. The rates mentioned here are based on the actual cost of water and electricity production, because most countries in the region are planning to reduce Danfoss FlatStations Tried & Trusted. www.sav-systems.com/danfoss-cibse SERIES HIU 46 June 2022 www.cibsejournal.com CIBSE June 22 pp46-48 Chiller in Middle East.indd 46 27/05/2022 15:38