The fast growing economy has increased energy use and resulted in problems including pollution and resource depletion. Reducing energy consumptions and carbon emissions has therefore become a worldwide effort. An analysis on the overall power consumption distribution shows that air conditioners and their most energy-hungry chiller units constantly account for more than 40% of electricity use so they have become the top priority in the mission to save energy.
Sweltering temperatures in summer bring skyrocketing electricity consumption by air conditioners and people can forget about the goal to reduce energy use and carbon emissions. In response, the international community is starting to promote the new cooling seasonal performance factor (CSPF) standard, which can more accurately evaluate operating efficiency of air conditioners in real-life use scenarios compared to the conventional energy efficiency ratio (EER) that is calculated based on fixed criteria without considering ambient temperature and the variation of indoor cooling load. To keep up with international standards, the Ministry of Economic Affairs established CNS 3615 and started to include CSPF in Taiwan's national standards on January 1, 2016.
CSPF plays an important role in helping push the introduction of highly energy-efficient air conditioners, indicated Min-Yu Liou, manager, Commercial Air Conditioning Design Department, Tatung Company. Based on the current EER standard, Grade 1 water-cooled packaged air conditioning units are required to have an EER higher than 5.14. Manufacturers will have difficulty meeting the Grade 1 requirement if not using variable frequency technology. To a certain degree, CSPF offers some freedom for manufacturers to have better chances at challenging the highest grade product design. In addition, consumers also have more opportunities to choose a truly energy-efficient model.
Air-cooled chiller unit – a very attractive choice for its space saving feature
Liou continued to point out that Tatung has been making all efforts in developing air conditioning products with optimum energy efficiency in accordance with national energy standards. In terms of commercial air conditioners, the website of the Bureau of Energy, Ministry of Economic Affairs has a list of the manufacturers who have products meeting the energy efficiency standards for chiller units of air conditioning systems, and Tatung has obtained a total of 65 certificates, far surpassing competitors. It should be noted that Tatung is one of the only two manufacturers that have received certificates for air-cooled fixed capacity chiller units.
In general, Tatung offers a wide variety of chiller units and has the highest number of models meeting energy efficiency standards, which represents their reliable quality and performance, commented Chien-Hsiu Huang, manager, Air Conditioning Business Planning Department, Tatung Company.
Chiller units with air-cooled condensers are distinguished from common water-cooled units in that they do not need cooling water towers but only require essential components including air handling units and indoor air supply units. This means savings on both cost and space for business owners as they will not need to build an equipment room and can place the chiller unit at an outdoor location with natural ventilation. Tatung has accumulated 23 energy efficiency certifications for its air-cooled chiller units. These products with their built-in advantages are extremely competitive for use at small- to medium-sized commercial areas. For example, a university recently purchased two Tatung 20-ton air-cooled chiller units in consideration of the cost and space saving advantages.
Liou indicated that besides focusing on air-cooled chiller units, Tatung is also developing small water-cooled chiller units that offer space saving features to encourage more business owners to opt for highly energy-efficient air conditioners.
Special parallel design raises energy-efficiency by over 30%
Another highlight of Tatung's commercial air conditioning systems is the use of parallel chiller units with chilled water as the conductive medium, achieving an energy saving efficiency surpassing common chillers by over 30%.
Huang explains the parallel system design is similar to the VRV variable-frequency and multi-connected air conditioner. The VRV design aims to allow multiple compartments to simultaneously cool down when one of the connected units is in operation. Tatung's parallel system has a similar structure except it uses chilled water as the medium while the VRV uses refrigerant. Take the 40-ton conventional chiller unit for example. Usually, one 10-ton compressor and one 10-ton heat exchanger make up an independent system and four such independent systems form a chiller unit. In order to obtain 100% heat exchange capacity, there is no other way but to run four compressors at the same time. Parallel chiller units offer a breakthrough from such limitation.
Compared to the same 40-ton conventional model, although Tatung's parallel system also comprises four compressors, it abandons the independent system design and its four compressors share the use of a large 40-ton heat exchanger. This design allows the user to achieve 100% heat exchange capacity with only one or two compressors running at a low cooling load. This translates to 1/3 to 1/2 savings on the electricity use without diminishing the cooling effects at all.
Despite the design similarity between parallel chiller units and VRV units, the two target different market segments. VRV units aim to replace large-scale packaged air conditioners while parallel chiller units look to take over conventional chiller units with independent structural design. Unlike VRV units, the manufacturing of parallel chiller units does not involve complicated processes, such as refrigerant pipe covering, filling and welding so the production costs are lower than VRV units. The largest parallel chiller unit Tatung offers now is a 120-ton system that is suitable for spaces from 1,587 square meters to 1,984 square meters, if not considering factors such as sunlight exposure and heat insulation.