scholarly journals Testing of a Radiant Wall Cooling System with Pipes Coupled to Aerated Blocks

2021 ◽  
Author(s):  
Martin Šimko ◽  
Dušan Petráš ◽  
Michal Krajčík ◽  
Daniel Szabó
Keyword(s):  
Surface Temperature ◽  
Cooling System ◽  
Thermal Response ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Dew Point ◽  
Outdoor Environment ◽  
Design Parameters ◽  
Indoor Climate ◽  
Thermal Output

Thermal output, surface temperatures, and supply and return water temperature were measured for a wall cooling system involving pipe attached to a wall section made of thermally insulating blocks. The experiment was performed for warm climatic conditions typical of, e.g., summer in Central and Northern Europe. The outdoor environment was simulated by a climatic chamber while the indoor climate was simulated by attaching a hotbox to the wall surface. The sensitivity of thermal output to several design parameters was investigated by 2D numerical simulations. The measurements showed a fast thermal response of the wall system. The cooling output was 38.3 W per m2 of the cooling area which equalled about 4.8 W/m2 per 1 K temperature difference between water and hotbox. The lowest surface temperature of 19.6 °C was measured at the pipe. Thus, the cooling output could be enhanced by reducing the surface temperature closer to the dew point temperature. The temperature of water in the pipe was very close to the surface temperature. It was illustrated how this characteristic of the wall cooling system tested positively affects the efficiency and cooling capacity of an air-to-water heat pump.

Economics of Gas Turbine Inlet Air Cooling System for Power Enhancement

1996 ◽  
Author(s):  
Motoaki Utamura ◽  
Yoshio Nishimura ◽  
Akira Ishikawa ◽  
Nobuo Ando
Keyword(s):  
Power Generation ◽  
Thermal Energy ◽  
Cooling System ◽  
Electric Energy ◽  
Dew Point ◽  
Design Parameters ◽  
Air Cooling ◽  
Power Enhancement ◽  
Air Cooling System ◽  
Running Cost

A cost estimate method is presented, which enables to compare inlet air cooling system for power enhancement of combustion turbine with other power generation system. A new energy conversion index is developed which arranges system design parameters in a dimensionless form and also exhibits running cost. It is suggested that the inlet air cooling system is equivalent to simple cycle or pumped storage in view of the dimensionless running cost. Next, a cost diagram relating capital cost to power generation cost is presented also in non-dimensional form, which could provide a measure to examine investment worth for a power producer. Moreover, cooling effectiveness as function of cooled inlet air temperature is investigated using specific thermal energy. It is revealed that cooling beyond dew point requires a larger thermal energy per electric energy produced and thus less economical unless the price of electricity depends on electricity demand.

scholarly journals Gas turbine unite inlet air cooling by using an excessive refrigeration capacity of absorption-ejector chiller in booster air cooler

2018 ◽  
Vol 70 ◽  
pp. 03012 ◽  
Author(s):  
Roman Radchenko ◽  
Andrii Radchenko ◽  
Serhiy Serbin ◽  
Serhiy Kantor ◽  
Bohdan Portnoi
Keyword(s):  
Gas Turbine ◽  
Cooling System ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Two Stage ◽  
Air Cooler ◽  
Refrigeration Capacity ◽  
Heat Loads

Two-stage Gas turbine unite (GTU) inlet air cooling by absorption lithium-bromide chiller (ACh) to the temperature 15 °C and by refrigerant ejector chiller (ECh) to 10 °C through utilizing the turbine exhaust gas heat for changeable ambient air temperatures and corresponding heat loads on the air coolers for the south Ukraine climatic conditions is analysed. An excessive refrigeration capacity of combined absorption-ejector chiller (AECh) exceeding the current heat loads and generated at decreased heat loads on the air coolers at the inlet of GTU can be used for covering increased heat loads to reduce the refrigeration capacity of AECh. The GTU inlet air cooling system with an ambient air precooling booster stage and a base two-stage cooling air to the temperature 10 °C by AECh is proposed. The AECh excessive cooling capacity generated during decreased heat loads on the GTU inlet air coolers is conserved in the thermal accumulator and used for GTU inlet air precooling in a booster stage of air cooler during increased heat loads. There is AECh cooling capacity reduction by 50% due to the use of a booster stage for precooling GTU inlet ambient air at the expense of an excessive cooling capacity accumulated in the thermal storage.

scholarly journals Experimental Performance Evaluation of an Integrated Solar-Driven Adsorption System in Terms of Thermal Storage and Cooling Capacity

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5931
Author(s):  
M.T. Nitsas ◽  
E.G. Papoutsis ◽  
I.P. Koronaki
Keyword(s):  
Energy Production ◽  
Cooling System ◽  
Thermal Storage ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Environmentally Benign ◽  
Heat Sources ◽  
Adsorption Chiller ◽  
Solar Cooling ◽  
Dual Bed

Heat-driven coolers provide a reliable and environmentally benign alternative to traditional electrically powered chillers. Their main advantage is that they can be driven using low enthalpy heat sources. A solar system is installed at the school of Mechanical Engineering of National Technical University of Athens in order to examine the potential of thermal storage and solar cooling under Athens climatic conditions. The cooling effect is produced using a dual bed, single stage, zeolite/water adsorption chiller with cooling capacity of 10 kW at its nominal conditions of operation. Both vacuum tube collectors and hybrid photovoltaic thermal collectors are installed in order to supply the system with heat. The system is evaluated in terms of solar collectors’ useful energy production, heat stored in the intermediate buffer and cooling system’s performance. It is observed that the cooling system operates satisfactorily under Athens climatic conditions achieving a maximum cooling capacity of 3.7 kW and an average COP around 0.5.

scholarly journals Performance estimation of membrane dehumidification based on heat exchanger analogy approaches using ε-NTU model

2020 ◽  
Vol 15 (2) ◽  
pp. 299-307
Author(s):  
Gilbong Lee ◽  
Chul Woo Roh ◽  
Bong Soo Choi ◽  
Eunseok Wang ◽  
Ho-Sang Ra ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Cooling System ◽  
Design Guidelines ◽  
Performance Estimation ◽  
Department Of Energy ◽  
Dew Point ◽  
Design Parameters ◽  
Evaporator Temperature ◽  
Vapour Compression

Abstract Reports by the US Department of Energy in 2014 evaluated membrane heat pump technology as one of the most promising alternatives to conventional vapour compression methods. Vapour compression methods maintain an evaporator temperature lower than the dew point to deal with the latent heat load. In membrane heat pump systems, only the water vapour is transferred and there is no phase change. The migration is caused by the difference in vapour pressure before and after the membrane. A vacuum pump or blower is used to create the pressure difference. However, there is no methodology for predicting dehumidification performance of membranes when used as part of a cooling system. In this study, using the assumption that there is a similarity between heat transfer and moisture pervaporation, the performance indices of the membrane are derived using a well-known heat exchanger method, the ε-NTU models. Performance estimations are calculated for two representative system layouts: bypass and vacuum. Simple relations between design parameters are suggested, giving design guidelines for researchers.

Research on Heat-Transfer Process of the Radiant Ceiling Cooling System

2012 ◽  
Vol 512-515 ◽  
pp. 2171-2174 ◽  
Author(s):  
Quan Ying Yan ◽  
Ran Huo ◽  
Li Li Jin
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Cooling System ◽  
Numerical Models ◽  
Cooling Water ◽  
Lower Surface ◽  
Cooling Capacity ◽  
Heat Transfer Process ◽  
Lower Surface Temperature ◽  
Selection Of

Physical and numerical models of the radiant ceiling cooling system were built and numerically simulated. The results showed that the lower the temperature of cooling water is, the lower surface temperature the ceiling has, and the bigger the cooling capacity is. The bigger the depth of tubes is, the higher the surface temperature and the smaller the cooling capacity. The differences are not evident. The bigger the distance of tubes is, the bigger the surface temperature is and the smaller the cooling capacity is. The diameter of tubes has a few influences on the surface temperature and the cooling capacity. Results in this paper can provide basis and guide for the design of the project, the selection of parameters and the feasibility of the system.

scholarly journals Laboratory tests of a prototypical user-centric radiant cooling solution

2021 ◽  
Vol 2069 (1) ◽  
pp. 012122
Author(s):  
H Teufl ◽  
M Schuss ◽  
A Mahdavi
Keyword(s):  
Surface Temperature ◽  
Cooling System ◽  
Dew Point ◽  
Cooling Systems ◽  
Efficient Operation ◽  
Radiant Cooling ◽  
Close Proximity ◽  
Free Cooling ◽  
Condensed Water ◽  
Vapour Condensation

Abstract Radiant cooling systems are being increasingly promoted because of their energy efficient operation as well as their potential to improve occupants’ thermal comfort due to a draft-free cooling process. This paper focuses on a specific radiant cooling approach, which was introduced in previous contributions. This approach involves the positioning of relatively small-sized vertical radiant panels in the close proximity to occupants. Furthermore, the panels incorporate drainage systems or collection elements to accommodate, if needed, water vapour condensation. Consequently, the surface temperature of the radiant panels does not need to stay above the dew point temperature. We present the outcome of a preliminary experimental investigation of such a personal radiant cooling system. In this context, prototypical radiant panels were installed in a laboratory and multiple experiments were conducted. The uniformity level of the panels’ surface temperature distribution was documented. Moreover, near-panel air flow velocities were measured at several positions. Likewise, the formation of condensed water on panels was observed for different panel surface temperatures, room temperatures, and room humidity levels. The results of the preliminary laboratory investigation do not point to any risk of draft or turbulence discomfort.

scholarly journals Innovative Turbine Intake Air Cooling Systems and Their Rational Designing

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6201
Author(s):  
Andrii Radchenko ◽  
Eugeniy Trushliakov ◽  
Krzysztof Kosowski ◽  
Dariusz Mikielewicz ◽  
Mykola Radchenko
Keyword(s):  
Gas Turbines ◽  
Maximum Rate ◽  
Cooling System ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Thermal Loads ◽  
Cooling Systems ◽  
Air Cooling System

The efficiency of cooling ambient air at the inlet of gas turbines in temperate climatic conditions was analyzed and reserves for its enhancing through deep cooling were revealed. A method of logical analysis of the actual operation efficiency of turbine intake air cooling systems in real varying environment, supplemented by the simplest numerical simulation was used to synthesize new solutions. As a result, a novel trend in engine intake air cooling to 7 or 10 °C in temperate climatic conditions by two-stage cooling in chillers of combined type, providing an annual fuel saving of practically 50%, surpasses its value gained due to traditional air cooling to about 15 °C in absorption lithium-bromide chiller of a simple cycle, and is proposed. On analyzing the actual efficiency of turbine intake air cooling system, the current changes in thermal loads on the system in response to varying ambient air parameters were taken into account and annual fuel reduction was considered to be a primary criterion, as an example. The improved methodology of the engine intake air cooling system designing based on the annual effect due to cooling was developed. It involves determining the optimal value of cooling capacity, providing the minimum system sizes at maximum rate of annual effect increment, and its rational value, providing a close to maximum annual effect without system oversizing at the second maximum rate of annual effect increment within the range beyond the first maximum rate. The rational value of design cooling capacity provides practically the maximum annual fuel saving but with the sizes of cooling systems reduced by 15 to 20% due to the correspondingly reduced design cooling capacity of the systems as compared with their values defined by traditional designing focused to cover current peaked short-term thermal loads. The optimal value of cooling capacity providing the minimum sizes of cooling system is very reasonable for applying the energy saving technologies, for instance, based on the thermal storage with accumulating excessive (not consumed) cooling capacities at lowered current thermal loads to cover the peak loads. The application of developed methodology enables revealing the thermal potential for enhancing the efficiency of any combustion engine (gas turbines and engines, internal combustion engines, etc.).

scholarly journals A Novel Low-Energy Ventilative Cooling System for Sustainable Built Environment

2016 ◽  
Vol 08 (1) ◽  
Keyword(s):  
Built Environment ◽  
Cooling System ◽  
Three Dimensional ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Navier Stokes ◽  
Working Fluid ◽  
Wind Speeds ◽  
Horizontal Orientation ◽  
Energy Equations

A numerical investigation into determining the thermal and ventilation capability of wind towers integrated with the heat pipe technology was carried out in this work. The water-charged copper heat pipes were systematically arranged in a horizontal orientation and integrated inside a modern roof-mounted wind tower. Water was used as the working fluid instead of synthetic refrigerants in order to make the system carbon-neutral alongside maintaining the indoor air quality of the built environment. The three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations along with the momentum, continuity and energy equations were solved using the commercial Computational Fluid Dynamics (CFD) ANSYS code for velocity and pressure field simulations. Using the inlet wind speeds ranging from 1m/s to 5m/s, the results of the study showed that the proposed cooling system was capable of meeting the regulatory fresh air intake requirements per occupant of 10L/s. In addition, the findings determined that a passive cooling capacity of up to 11K was achievable when the system was subjected to inlet temperatures of 310K or 37°C. The work characterised the sustainable operation of wind tower in delivering energy-free ventilative cooling in regions encompassing hot and dry climatic conditions. The technology presented in this work is currently under an Intellectual Property (IP) protection (GB1321709.6).

scholarly journals METHODOLOGY FOR DETERMINING THE MAIN INDICATORS OF THE TEMPERATURE AND DYNAMIC CHARACTERISTICS OF THE COOLING SYSTEM OF AN ENERGY VEHICLE DURING OPERATION

2021 ◽  
pp. 75-79
Author(s):  
Ekaterina Parlyuk ◽  
Nikolay Bol'shakov
Keyword(s):  
Internal Combustion Engines ◽  
Cooling System ◽  
Climatic Conditions ◽  
Thermal Balance ◽  
Operating Conditions ◽  
Design Parameters ◽  
Industrial Complex ◽  
Design Features ◽  
Engine Operation ◽  
Temperature Dynamic

The efficiency of internal combustion engines of energy facilities operating in the conditions of enterprises of the agro-industrial complex depends on the stability of the thermal regime of the engine. Its provision is entrusted to the cooling system, in this article which is a radiator with a polyurethane core. The temperature regime of the engine operation affecting a number of factors is given and described - these are design parameters (design features of the radiator and the features of the working process of the radiator, taking into account the operating conditions of the tractor) and operational, which take into account the operating mode of the tractor and natural and climatic conditions. According to the research results during the operation of the tractor in steady conditions, the temperature of the coolant in the system is stable, respectively, the temperature field of the air flow at the inlet and outlet of the radiator with a polyurethane core also stabilizes. To take them into account, the coefficient of thermal properties of the radiator is introduced, which depends on the external and internal temperature-dynamic effects of the environment, and a diagram is constructed that shows the dependence of the temperature of the coolant flowing in the radiator on the generated load of the tractor during operation in the field. At the same time, the temperature-dynamic characteristic of the tractor does not depend on the design features of the engine, but on the power developed by the engine. Therefore, the heat removed from the engine into the coolant is calculated by us through the engine power. Based on this, the characteristic of the thermal balance of the engine and the heat transfer of the radiator during the operation of the tractor at full load are considered, taking into account the change in gears within the speed limits, a graph of the thermal balance of the engine and radiator versus speed is built. Based on the calculations, it was concluded that the use of the characteristics of the traction-dynamic balance of the tractor can serve as the basis for the general analysis and calculated and experimental operating modes of the automotive polymer radiator and the cooling system as a whole, taking into account the loads, climatic conditions and operating parameters of the cooling system

Adaptability Analysis of New Ceiling Radiant Cooling Panels with Dedicated Outdoor Air Systems Used in Summer Moist Heat Regions

2012 ◽  
Vol 517 ◽  
pp. 864-869 ◽  
Author(s):  
Xu Han Zhang ◽  
Nian Ping Li ◽  
Jian Guang Yang
Keyword(s):  
Energy Conservation ◽  
Surface Temperature ◽  
Cooling Capacity ◽  
Design Parameters ◽  
Outdoor Air ◽  
Moist Heat ◽  
Radiant Cooling ◽  
System Components ◽  
Major Defect ◽  
New System

This paper introduces the operating principle and system components of Ceiling Radiant Cooling Panels (CRCP) with Dedicated Outdoor Air Systems (DOAS), moreover, analyses not only the advantages of CRCP/DOAS system in terms of comfort, energy conservation and healthy environmental protection, but also the three obstacles to the system when running in summer moist heat regions condensation, radiant cooling capacity and first cost. The major defect of CRCP is proposed that the surface temperature of the panel is uneven, while the shortage of DOAS is the insufficiency of outdoor air handling. A new CRCP/DOAS system is provided in this paper, including patent radiant cooling panel and patent air condition. We also expound the characteristics of this new system, and list the recommended design parameters as well.

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