Calculation of marine air conditioning systems based on energy savings

The development of ship propulsion in the areas of Economic Operation, Environmental Protection and Ship Efficiency (Triple E - Economy, Environment, Efficiency) is the comparison standard of the manufacturers of contemporary ships. The standard is based on the application of a more modern design of the diesel engines, the wide use of waste heat and the efficient operation of the ship.In accordance with the Economic Operation, the need to evaluate the design of air conditioning systems has been identified in order to determine the possible savings, which are represented by a decrease in fuel consumption, as a result of: the significant impact of this consumption in the operation of the ship, the current high costs of this energy, the periodic increase in the price of the same, and the international policies for the reduction of emissions to the atmosphere and preservation of the environment.By means of the energy diagnosis of the air conditioning system it is possible to determine the possible opportunities of energy saving during the operation of the ship.The results indicate that the thermal load and the cooling capacity required by the air conditioned spaces have a difference between their maximum and average value of 14%. This justifies the need to use a conditioning system with a variable volume of air supplied to the air conditioned space.

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Towards energy efficient operation of Heating, Ventilation and Air Conditioning systems via advanced supervisory control design

Journal of Physics Conference Series ◽

10.1088/1742-6596/659/1/012030 ◽

2015 ◽

Vol 659 ◽

pp. 012030

Author(s):

A Oswiecinska ◽

J Hibbs ◽

I Zajic ◽

K J Burnham

Keyword(s):

Supervisory Control ◽

Energy Efficient ◽

Air Conditioning ◽

Control Design ◽

Efficient Operation ◽

Air Conditioning Systems

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Thermal Energy Requirements of Air-Conditioning Systems

Journal of Engineering for Power ◽

10.1115/1.3445548 ◽

1971 ◽

Vol 93 (2) ◽

pp. 172-176

Author(s):

M. E. Lackey

Keyword(s):

Thermal Energy ◽

Air Conditioning ◽

Waste Heat ◽

Energy Requirements ◽

Absorption Refrigeration ◽

Refrigeration System ◽

Fast Breeder Reactors ◽

Breeder Reactors ◽

Absorption Refrigeration System ◽

Air Conditioning Systems

The thermal energy requirements for air conditioning by compressive and absorption methods were determined for light-water, thermal-breeder, and fast-breeder reactors. The energy required to produce a ton-hour of refrigeration varied from 5100 Btu to 13,100 Btu by absorption and from 5600 to 8800 Btu by compression. The amount of waste heat dissipated to the environment at the reactor site as a consequence of producing a ton-hour of air conditioning ranged from an increase of 21,000 Btu for the electric-motor-driven refrigeration system to a decrease of 6000 Btu for the absorption refrigeration system.

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Refrigerating fluid with a low global warming potential for automotive air conditioning systems in summer

Thermal Science ◽

10.2298/tsci200308045m ◽

2021 ◽

pp. 45-45

Author(s):

Zhaofeng Meng ◽

Yin Liu ◽

Dingbiao Wang ◽

Long Gao ◽

Junhai Yan

Keyword(s):

Global Warming ◽

Global Warming Potential ◽

Air Conditioning ◽

Cooling Capacity ◽

Automotive Air Conditioning ◽

Discharge Temperature ◽

Air Conditioning Systems ◽

Low Global Warming Potential ◽

Lower Discharge

Refrigerants with low global warming potential (GWP) are much needed in automotive air conditioning systems. This paper compares two refrigerants, R134a (GWP=1300) and R513A (GWP=573) experimentally. The results show that the latter has lower cooling capacity, lower COP and lower discharge temperature than the former, revealing that R513A is a promising replacement of its high GWP partner.

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Conversion of gas engine waste heat into cold using absorption chillers

E3S Web of Conferences ◽

10.1051/e3sconf/202016800046 ◽

2020 ◽

Vol 168 ◽

pp. 00046

Author(s):

Georgii Karman ◽

Yurii Oksen ◽

Olena Trofymova ◽

Yurii Komissarov ◽

Borys Dizhevskyi ◽

...

Keyword(s):

Air Conditioning ◽

Waste Heat ◽

Lithium Bromide ◽

Thermodynamic Cycle ◽

Cooling Capacity ◽

Coolant Temperature ◽

Gas Engine ◽

Absorption Chillers ◽

Full Conversion ◽

Heating Medium

A possibility of gas engine waste heat conversion into cold for air conditioning in mines using lithium bromide absorption chillers is investigated. Dependencies of parameters of a thermodynamic cycle and energy indicators of chillers on temperatures of a heating medium and a coolant are obtained using mathematical modelling. It is shown that it is rational to use two chillers with sequential movement of a heating medium and a coolant through them in opposite directions for a full conversion of gas engine waste heat. COP of such a system is 0.733. This allows obtaining 2140 kW of cooling capacity with a coolant temperature of 7 °C when using a gas engine JMS-620 by Jenbacher.

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Dynamic simulation of indirect air conditioning systems with optimized computational time

E3S Web of Conferences ◽

10.1051/e3sconf/201911104042 ◽

2019 ◽

Vol 111 ◽

pp. 04042

Author(s):

Nicolás Ablanque ◽

Santiago Torras ◽

Carles Oliet ◽

Joaquim Rigola ◽

Carlos-David Pérez-Segarra

Keyword(s):

Air Conditioning ◽

Energy Savings ◽

Control Strategies ◽

Model Potential ◽

Hvac Systems ◽

Object Oriented Programming ◽

Computational Time ◽

Air Conditioning System ◽

Numerical Resolution ◽

Air Conditioning Systems

The simulation of HVAC systems is a powerful tool to improve the energy efficiency in buildings. The modelling of such systems faces several obstacles due to both the physical phenomenology present and the numerical resolution difficulties. The present work is an attempt to develop a robust, fast, and accurate model for HVAC systems that can interact with the other relevant systems involved in buildings thermal management. The whole system model has been developed in the form of libraries under the Modelica language to exploit its advantageous characteristics: object-oriented programming, equationbased modelling, and handling of multi-physics. The global resolution is carried out dynamically so that not only steady-state predictions can be conducted but also control strategies can be studied over meaningful periods of time. This latter aspect is crucial for optimizing energy savings. The libraries include models for all the system individual components such as pumps, compressors or heat exchangers (operating with twophase flows and/or moist air) and also models assemblies to account for vapour compression units and liquid circuits. An illustrative example of an indirect air conditioning system is detailed in the present work in order to highlight the model potential.

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Analysis of the Behavior of an Air Conditioning System Based on the Solar Energy Natural Regulation in Amazonian Climatic Conditions

Journal of Solar Energy Engineering ◽

10.1115/1.4048275 ◽

2020 ◽

Vol 143 (3) ◽

Author(s):

Elson C. Santos ◽

Emanuel N. Macêdo ◽

Marcos A. B. Galhardo ◽

Thiago Oliveira Costa ◽

André Felipe P. Costa ◽

...

Keyword(s):

Direct Current ◽

Air Conditioning ◽

Cooling Capacity ◽

Climatic Conditions ◽

Power Modeling ◽

Frequency Converters ◽

Industrial Buildings ◽

Air Conditioning Systems ◽

Solar Resource ◽

Installed Capacity

Abstract Air conditioning systems (ACSs) represent one of the main demands for electricity in residential, commercial, and industrial buildings. The use of a photovoltaic air conditioning unit (PVACU) represents an attractive application to this demand for reasons such as environmental concerns and the match between diurnal cooling load and solar resource. A PVACU consists of a photovoltaic generator (PVG) that supply an ACS through direct current to direct current and frequency converters, without energy storage. This system considers the natural adjustment of the ACS cooling capacity according to the PVG power. Modeling the ACS, the PVG, and the thermal load (TL) makes possible to evaluate PVACU performance. For this, a small library’s TL and an ACS supplied by a PVG were used as case study. The PVG installed capacity assumes values of 700, 1000, and 1400 Wp. The simulation results show that the PVACU with a 1400 Wp PVG would be sufficient to regulate internal temperature within international comfort standards in the range of 20 °C to 24 °C. According to the data obtained in the simulations, it was possible to conclude that the PVACU has a large potential to be used in air conditioning of other environments in regions with Amazonian climatic conditions.

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Design and Analysis of a Thermoelectric Air-conditioning System

Journal of Scientific Research and Reports ◽

10.9734/jsrr/2020/v26i430243 ◽

2020 ◽

pp. 1-11

Author(s):

A. Anthony Adeyanju ◽

K. Manohar

Keyword(s):

Air Conditioning ◽

Thermoelectric Module ◽

Cooling Capacity ◽

Peltier Effect ◽

Refrigeration Cycle ◽

Air Conditioner ◽

Air Conditioning System ◽

Thermoelectric Air Conditioner ◽

Air Conditioning Systems ◽

Dc Current

Thermoelectric devices use the Peltier effect which creates a heat flux between the junctions of two different types of materials. The thermoelectric module also referred to as a heat pump transfers heat from one side to the other when a DC current is applied. This study carried out the theoretical and experimental analysis of a thermoelectric air conditioning system. A prototype thermoelectric air conditioner of 286 W cooling capacity was built and a testing enclosure made from plywood and Styrofoam was also constructed in order to validate the theoretical result with an experimentation. It was discovered that thermoelectric air conditioning took 4 minutes to reach its desired temperature of 22℃ whereas the standard air conditioning system (Refrigeration Cycle) took 20 minutes to cool to a room temperature. Economically it was also discovered that thermoelectric air conditioning system is 50% cheaper than the refrigeration cycle air conditioning systems. The thermoelectric air conditioner has cheaper maintenance and greater estimated life span of 7 years more than the refrigeration air conditioner. This is because the air conditioner that operates on the refrigeration cycle uses a rotating compressor while the thermoelectric air conditioner uses thermometric module.

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ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ СИСТЕМ КОНДИЦІЮВАННЯ ПОВІТРЯ ШЛЯХОМ РОЗПОДІЛУ ТЕПЛОВОГО НАВАНТАЖЕННЯ ЗА СТУПЕНЕВИМ ПРИНЦИПОМ

Aerospace technic and technology ◽

10.32620/aktt.2019.8.07 ◽

2019 ◽

pp. 49-53

Author(s):

Євген Іванович Трушляков ◽

Микола Іванович Радченко ◽

Андрій Миколайович Радченко ◽

Сергій Георгійович Фордуй ◽

Сергій Анатолійович Кантор ◽

...

Keyword(s):

Thermal Load ◽

Air Conditioning ◽

Rational Design ◽

Ambient Air ◽

Cooling Capacity ◽

Climatic Conditions ◽

Outlet Temperature ◽

Thermal Loads ◽

Air Conditioning System ◽

Air Conditioning Systems

Maintaining the operation of refrigeration compressors in nominal or close modes by selecting a rational design thermal load and distributing it in response to the behavior of the current thermal load according to the current climatic conditions is one of the promising reserves for improving the energy efficiency of air conditioning systems, which implementation ensures maximum or close to it in the annual cooling production according to air conditioning duties. In general case, the total range of current thermal loads of any air-conditioning system includes a range of unstable loads caused by precooling of ambient air with significant fluctuations in the cooling capacity according to current climatic conditions, and a range of relatively stable cooling capacity expended for further lowering the air temperature from a certain threshold temperature to the final outlet temperature. If a range of stable thermal load can be provided within operating a conventional compressor in a mode close to nominal, then precooling the ambient air with significant fluctuations in thermal load requires adjusting the cooling capacity by using a variable speed compressor or using the excess of heat accumulated at reduced load. Such a stage principle of cooling ensures the operation of refrigerating machines matching the behavior of current thermal loads of any air-conditioning system, whether the central air conditioning system with ambient air procession in the central air conditioner or its combination with the local indoors recirculation air conditioning systems in the air-conditioning system. in essence, as combinations of subsystems – precooling of ambient air with the regulation of cooling capacity and subsequent cooling air to the mouth of the set point temperature under relatively stable thermal load.

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The Experimental Assessment of R134a and Its Lower GWP Alternative R1234yf in an Automobile Air Conditioning System

Journal of Engineering ◽

10.31026/j.eng.2019.12.1 ◽

2019 ◽

Vol 25 (12) ◽

pp. 1-14

Author(s):

Rafah Hussain ◽

Issam Mohammed Ali

Keyword(s):

Ambient Temperature ◽

Air Conditioning ◽

Cooling Capacity ◽

Air Conditioning System ◽

Automotive Air Conditioning ◽

Nominal Capacity ◽

Automotive Air Conditioning System ◽

And Performance ◽

Air Conditioning Systems ◽

Main Operating

Reducing global warming potential (GWP) of refrigerants is needed to the decrease of ozone-depleting of refrigeration systems leakages. Refrigerant R1234yf is now used to substitute R134a inside mobile air conditioning systems. Thermodynamic properties of R1234yf are similar to R134a. Also, it has a very low GWP of 4, compared to 1430 for R134a, making it a proper choice for future automobile refrigerants. The purpose of this research is to represent the main operating and performance differences between R1234yf and R134a. Experimental analysis was carried out on the automotive air conditioning system (AACS) with 3 kW nominal capacity, to test and compare the performance of R134a with R1234yf. Experiments were accomplished for both refrigerants in almost the same working conditions and procedure with a range of ambient temperature varied from 26oC to 50oC. Parameters studied were ambient temperature, type of refrigerant in the system at compressor speed 1450 rpm, and internal thermal loads of passenger room. The performance characteristics of the system, including COP and cooling capacity, were studied by changing different parameters. The results show that COP of R134a is higher than R1234yf by 12.6%, while the refrigeration effect of R134a is higher than R1234yf by 25%. This shows that R1234yf is a suitable and good candidate for drop-in replacement of R134a in AACS.

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