Empowered to cool
In a region that is fast gravitating towards sustainable solutions, could a firm integration of renewable energy, particularly solar, be a game changer in the GCC district cooling industry?
The surge in construction developments within the GCC is already driving the district cooling industry to newer heights, with conspicuous growth in cooling capacity over the past decade. But as new players enter the industry and competition widens, efficiency is increasing being seen as the key to business survival.
Companies are now exploring the integration of renewable energies into the day-to-day operations of district cooling plants in a bid to minimise operational costs while at the same time wishing to be perceived as sustainable by their clients.
Renewable energy sources such as solar, wind and biomass are gradually being introduced at various stages of plant operations, a move that could eventually scale down end-user costs, according to industry players.
“Solar thermal systems (STS) for residential applications are a mature technology that have been successfully deployed in a number of countries for more than thirty years,” says Ahmad Bin Shafar, CEO, Emirates Central Cooling Systems Corporation (Empower).
“District energy schemes are one of the most effective means for integrating renewable energy sources into heating and cooling sectors. Solar thermal, geothermal, bioenergy, waste heat and natural, free, cooling systems can benefit from the economies of scale that district energy provides.”
In countries like Barbados, Cyprus and Israel, 80%-90% of residential homes have domestic solar water heating systems on their roofs. Globally, however, only 1.2% of space and water heating in the buildings sector is covered by STS.
With cooling demand in residential buildings accounting for 60%-87% of energy demand in buildings located in hot climates, there is a substantial potential for STS for domestic water and space heating, says Shafar.
Solar cooling has been growing rapidly from around 60 systems in 2004 to more than 1000 systems installed in 2013, according to the International Energy Renewable Agency (IRENA). IRENA adds that 17 large-scale solar district systems are connected to cooling networks in Europe. However, compared to the potential of using solar energy to generate cooling, deployment levels are very low, concludes IRENA.
Most deployment, 80%, is in Europe and a number of companies like EAW, Invensor, Sortech, SolarNext (Germany), Pink (Austria) Broad (China), Thermax (India), Yazaki, Kawasaki, Mistubishi (Japan) and Jangsu Huineng (China) have released small, commercial solar cooling.
“District cooling from solar energy is still a virgin area and that is why we think that it is worth venturing into. There all indications that solar can be a valuable resource in running a district cooling plant and Empower is now ready to give it a try,” says Bin Shafar.
Empower will early next year commission a study on the applicability of solar in its district cooling plants and hopes to start using solar across some of its operations by the end of 2017.
Solar cooling can be complementary to solar heating, especially in regions that require cooling in the summer and heating in the winter. In this particular case, an increase in collector area to allow for cooling would simultaneously allow for a larger solar share of domestic water and space heating by a typical solar combi-system in winter.
“This approach avoids any long stagnation periods during summer or winter and, at the same time, increases economic efficiency. The increased efficiency of advanced flat-plate and evacuated vacuum tube collectors makes it possible to add a thermally driven, adsorption or absorption cooling system to an existing solar combi-system, resulting in a so called solar plus combi-system,” says IRENA.
According to IRENA, there are three kinds of solar cooling systems: absorption chillers, adsorption chillers, and dessicant cooling systems. The technologies of solar space and water cooling are the same as those developed for gas cooling systems. In Europe, mostly ETC and FPC are used to provide heat, which can subsequently.
The technology to convert heat into cooling is mature and reliable, according to International Energy Group president and CEO engineer Yahya Lootah. Ironically, with abundant solar radiation in the GCC, it has not yet received much attention here. “The most likely reason for the lack of interest is the long payback time,” says Lootah.
According to traditional financial analysis, the payback period of solar cooling is often more than a decade.
The heat-activated refrigeration principle used mostly in solar cooling projects is absorption, as it is well-established for this application. There are currently two types of absorption chillers, namely ‘single-effect’ chillers requiring heat at 70 to 90 degree Celsius (meaning hot water can be used as the heat-transfer medium, thereby simplifying the heat-delivery mechanism greatly) and ‘double-effect’ chillers requiring heat at temperatures above boiling point (meaning pressurized water or steam has to be used).
Most small-scale systems below 50 TR are based on single-effect absorption chillers. This is not only because the requirements of a non-pressurised hot water system are much more consistent with budgetary constraints, but also because the need to achieve high temperatures means that some kind of optical concentration (‘parabolic’ or ‘compound parabolic’) has to be achieved, in conjunction with a sun-tracking mechanism – which immediately increases the total cost of the collectors by a factor of five.
Lootah also points out that “naturally, solar radiation can only provide a fraction of the required thermal energy used by the absorption chiller. For operation at night and during cloudy days in particular, it is necessary to burn gas.”
The integration of solar into district cooling operations is expected to naturally drive the market for solar products in the GCC, according to industry analysts.
There are already existing schemes in the GCC that envision a self-reliant district cooling plant that can generate its own electricity, a move that will bring down plant operation costs and also spare the further burning of fossil fuels to cater for the energy needs of the district cooling plants.
“We have built a trial district cooling plant in Dubai that generates its own energy to boost the overall efficiency of operations. We hope that the success at this plant will be replicated across existing and future district cooling plants,” says Saeed Mohammaed Al Tayer, CEO and managing director, Dubai Electricity and Water Authority (DEWA).
Until recently, Empower has targeted only new developments in Dubai for its district cooling services, mainly because newer buildings can easily and cheaply plan for all the infrastructural requirements of a district cooling network.
But now the company is venturing into retrofit of existing buildings to link them to its district cooling plants.
“The retrofit business is just starting, although it will progress in stages. In the past, we have worked with new developments or areas that have been rebuilt. But we now see a real growing need for retrofitting,” says Bin Shafar.
Empower in 2015 connected the Emirates Towers development to its district cooling network serving Dubai International Financial Centre (DIFC). The company converted the existing air cooled system to district cooling system for the total capacity of 6,000 Refrigeration Tonnes (RT), resulting in energy savings of approximately 80%, and nearly $4.35mn annually.
The Jumeirah Group-owned property consists of the Emirates Office Tower and Jumeirah Emirates Towers Hotel that are connected with a two-storey retail complex known as "The Boulevard".
“The conversion from traditional cooling to district cooling for this capacity was the first of its kind in Dubai and has set the benchmark for other developments utilising traditional systems of cooling,” says Bin Shafar.
Empower retrofits cover several properties including Jumeirah Emirates Towers, Burj Al Arab Jumeirah, Jumeirah Beach Hotel, Emirates Academy of Hospitality Management and Madinat Jumeirah, which includes the existing three hotels – Al Qasr, Mina A’Salam and Dar Al Masyaf – as well as the conference facilities, Souk Madinat and the 340-room extension to Madinat Jumeirah, which is currently under construction.
Empower also recently completed the district cooling infrastructure project network for Damac Towers by Paramount’ which consist of four towers including an international hotel.
The company is now exploring district cooling opportunities in other Emirates and countries where it can leverage its expertise in the industry to widen its market base.
Last year, Empower signed a memorandum of understanding (MOU) with German Energy firm RWE AG with the aim of exchanging expertise and reviewing latest developments in the renewable energy and district cooling areas. The move will help Empower to streamline its offerings and further widen its prospects.
Both Empower and RWE are keen on promoting knowledge exchange in district cooling as part of a wider drive towards energy efficiency.
“We continue to explore new technologies that increase the district cooling efficiency to guarantee compliance with the smart and sustainable transition requirements. We are keen on promoting knowledge exchange in district cooling as part of a wider drive towards energy efficiency,” says Bin Shafar.