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Facilities and Operating Sources
Published in Rengasamy Kasinathan, Environmental Compliance Guide for Facility Managers and Engineers, 2023
Buildings should have controlled temperature, humidity, and ventilation for the space in order to ensure the health, comfort, and productivity of their occupants, especially hospitals where patients are of most importance. Chillers are part of a facility's HVAC system and are used in processes where chilled water or liquid are needed.
Boiler Operator's Handbook
Published in Carl Bozzuto, Boiler Operator's Handbook, 2021
Sometimes, people, experienced with the need for superheat to control the flow through the throttling device, will insist that the gas leaving the evaporator of a chiller has to be superheated. That is not the case with centrifugal chillers. The throttling device in a centrifugal chiller is a float valve (Figure 5-22) and normally consists of two float valves that separate two different pressures. The system of two float valves, and the chamber between them, is commonly called an economizer because it captures some of the vapor that flashes as the pressure is dropped and uses it to cool the hermetic motor of the chiller, entering the compressor between two stages. That system saves the compressor from pumping all of the gas from the evaporator pressure to the condenser pressure. Being a large and expensive machine, they are normally insured. The insurers typically require a breakdown inspection of a chiller every 15 years. Examinations include electrical insulation testing, leak testing, and eddy current testing of the tubes. There is a hint here. The typical chiller is expected to operate for 15 years without concern. It is a highly reliable piece of equipment.
Typical Pre-Commissioining and Start-Up Procedures
Published in Maija Virta, HVAC Commissioning Guidebook, 2021
A chiller is a machine that removes heat from a liquid, typically via a vapor-compression (Fig. 7.27 and 7.30.), absorption or adsorption refrigeration cycle. This liquid can then be circulated through a heat exchanger to cool air or equipment as required. As a necessary by-product, refrigeration creates waste heat that must be exhausted to ambient or, for greater efficiency, recovered for heating purposes. [73]
Adaptive data-driven optimization of chiller loading with domain knowledge
Published in Science and Technology for the Built Environment, 2021
Wantao Shi, Xinqiao Jin, Jiangqing Wang, Zhimin Du
In HVAC systems, chillers are widely used to provide the cooling load, and are one of the major energy-consuming equipment (Salari and Askarzadeh 2015). For commercial buildings, chillers with the same or different cooling capacities are often installed to satisfy the cooling requirements. In such systems, it is very important to optimize the chiller loading during the different operation conditions for energy conservation (Yu et al. 2020). Therefore, how to operate chillers to minimize the chillers’ energy consumption while satisfying the cooling requirements becomes an important issue (Sun, Wang, and Huang 2009). Recently, many researches on the optimal chiller loading (OCL) have been reported. These studies can be divided into two categories, namely: model-based control and model-free control.
Evidence-based assessment of energy performance of two large centrifugal chillers over nine cooling seasons
Published in Science and Technology for the Built Environment, 2021
Vapor-compression electric centrifugal chillers, installed in commercial and institutional buildings, have an important contribution to the whole building energy use. Chillers of capacities of 264 to 2640 kW (75- to 750-ton refrigeration) have a median service life of more than 25 years (ASHRAE 2019). They are usually designed for a lifetime of 40 years or more (Blahnik and Klein 1993), and they can exceed this lifetime if operations, maintenance, service water, and operating environment are properly managed and controlled. For comparison, window-type air conditioners have a lifetime of 10 years, residential single or split package 15 years, residential and commercial air-to-air heat pumps 15 years, and commercial water-to-air heat pumps have more than 24 years (ASHRAE 2019).
A feature importance ranking based fault diagnosis method for variable-speed screw chiller
Published in Science and Technology for the Built Environment, 2022
Hailong Lu, Xiaoyu Cui, Hua Han, Yuqiang Fan, Yunqian Zhang
The cost of chiller testing is extremely high, and fault simulation test usually requires to cover all operational conditions. In order to save cost, this paper chooses to study the specific fault of chiller based on the needs of chiller manufacturers. Refrigerant leakage and overcharge have appeared higher frequency among chiller faults, and will take great impact on chiller’s stable and efficient operation. In serious cases, refrigerant leakage and overcharge will directly lead to failure shutdown or even compressor damage, so the diagnosis of refrigerant leakage and overcharge of variable-speed screw chiller is determined as the research content of this paper.