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Energy-efficient thermal energy generation and distribution in buildings
Published in Paul Tymkow, Savvas Tassou, Maria Kolokotroni, Hussam Jouhara, Building Services Design for Energy-Efficient Buildings, 2020
Paul Tymkow, Savvas Tassou, Maria Kolokotroni, Hussam Jouhara
For a refrigeration system, COPwf=h1−h4h2−h1and for a heat pump system, COPhp=h2−h3h2−h1 The cooling capacity of the refrigeration system can be calculated by multiplying the refrigeration effect by the refrigerant flow rate in the system.
Ventilation Operating Costs
Published in William Popendorf, Industrial Hygiene Control of Airborne Chemical Hazards, 2019
The capacity of a refrigeration unit is the rate at which it can extract heat. A system’s cooling capacity is sometimes expressed in terms of “tons of refrigeration” which is equivalent to 12,000 Btu/h or 200 Btu/min. This term has an interesting history. One ton of refrigeration is the rate produced by melting 1 ton of ice at 32°F (0°C) in 24 h. This historical form of refrigeration was used a hundred years ago for food storage and (if one were rich enough) to cool some occupied rooms by storing ice from the winter and melting it in the summer. While that era has passed, the unit is still used by many HVAC practitioners within the air conditioning and refrigeration industry.
Electric End Uses
Published in J. Lawrence, P.E. Vogt, Electricity Pricing, 2017
Cool air is attained by running the heat pump’s thermodynamic cycle in reverse in order to move heat out of the building, thus cooling the inside air. Cool or cold air is merely air which contains little thermal energy. Conventional air conditioning operates on the same principle as the heat pump’s cooling cycle. The cooling capacity of an air conditioner is rated in Btu per hour, and 12,000 Btu/hr is equal to one ton of refrigeration. The Btu rating is an indication of how much heat can be moved in an hour.
Comprehensive analysis of a novel cooling/electricity cogeneration system driven by waste heat of a marine diesel engine
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Milad Feili, Maryam Hasanzadeh, Hadi Ghaebi, Ebrahim Abdi Aghdam
In the first step, the effects of the VG1 operating pressure on chief performance factors are demonstrated in Figure 4. Accordingly, it can be said that by increasing the pressure of vapor generator 1 in the range of 20 to 25 bar, the amount of strong vapor solution released from the VG1 is decreased, while the inlet pressure of the turbine is increased. According to Figure 4, the electricity capacity of the turbine reaches its maximum value of 46.71 kW by increasing the pressure to 23.21 bar and then reduced based on the vapor mass flow rate. As the pressure increases, the temperature of cooled gas leaves the VG 1 rises. This phenomenon causes more heat to be injected into the cooling cycle. As a result, the refrigerant temperature at the outlet of the VG 2, which is defined via terminal temperature difference, rises. Then according to the energy balance equation and fixing the final temperature of cooled gas at 375.15 K, the mass flow rate of refrigerant passing through VG 2 increases. Broadly speaking, increasing the mass flow rate of the cooling cycle is recommended in terms of cooling capacity.
Thermoeconomic performance optimization of an orifice pulse tube refrigerator
Published in Science and Technology for the Built Environment, 2020
Debashis Panda, Ashok K. Satapathy, Sunil K. Sarangi
Pulse tube refrigerators (PTRs) are most suitable cryogenic refrigerators for the cooling of high temperature superconducting (HTS) magnets, HTS motors, generators and transformers, liquefaction of permanent gases presents in the atmosphere, cooling of charcoal absorbers in the cryopumping processes, etc. (De Waele 2011; Radebaugh 2009). This is because of its additional benefits over other cryogenic refrigerators, such as compact size, user-friendly operation, absence of reciprocating components in its low-temperature side, no wear and tear, less vibration, absence of seals, and long mean time between maintenance. Also, due to the application of HTS motors in the electrical vehicle propulsion system to lessen the power consumption rates, an increase in thermodynamic performance of PTRs is mostly necessary (Nakano, Yumoto, and Hiratsuka 2015). Therefore, it is imperative to enhance its cooling capacity and overall thermodynamic efficiency to increase its region of application. This unique and novel cryogenic refrigerator operates on the thermodynamic principle of surface heat pumping (i.e. compression and expansion of gas parcels inside the pulse tube) to produce the cooling effect. Thereafter, numerous independent theories have been introduced and geometrical modifications have been suggested to enhance its thermodynamic performance (De Waele 2011).
Optimizing single-stage double-effect LiBr-H2O absorption chiller in micro-trigeneration system using an atom search optimization algorithm
Published in Science and Technology for the Built Environment, 2022
Sunil D. Bagade, Prasad B. Rampure
It is noted that the cooling capacity of the proposed system is increased by temperature reduction. In the comparison of the system's cooling efficiency before and after optimization, a temperature of 262 K is attained at 16 kW, while before optimization, it was 268 K at 16 kW. Hence, from the results, this optimization of the proposed system is efficient.