Experiences With Thermal Driven, Desiccant Assisted Air Conditioning Systems in Germany

2007 ◽  
Author(s):  
G. Schmitz ◽  
A. Joos ◽  
W. Casas
Keyword(s):  
Air Conditioning ◽  
Power Plants ◽  
Energy Savings ◽  
Measurement Data ◽  
Electricity Consumption ◽  
Heating System ◽  
Primary Energy ◽  
Dew Point ◽  
Water Evaporation ◽  
Air Conditioning Systems

During summer, the use of conventional electrically driven air conditioning systems often results in high electricity consumption. On the other hand, heat demand is very low, therefore heat from Combined Heat and Power plants (CHP) or from solar collectors can not be used. Thermal driven desiccant assisted air conditioning systems offer the possibility to shift energy requirements from electricity to heat. Furthermore, as sorptive pre-drying air doesn’t require cooling under dew point for dehumidifying nor any subsequent heating, cold sources at higher temperatures (e.g. 18°C) can be used for cooling. Within the scope of research projects, different demonstration plants for office buildings and a private bungalow were built, where the operations were evaluated by the Hamburg University of Technology. One plant combines a desiccant wheel with a small (5 kWel) gas driven co-generation plant. Instead of an electric chiller or a water evaporation system (desiccant evaporating cooling), borehole heat exchangers in combination with a radiant floor heating system were used for cooling in summer. In this paper, performance comparisons with conventional systems based on numerical simulations and measurement data are shown, including a cost analysis. It is found that the combination of desiccant wheels and earth energy systems offers considerable energy savings compared to conventional electric systems. The operation of such systems is also cost-effective. It can lead to a reduction of up to 28% of primary energy consumption in a whole year compared to a conventional A/C system.

scholarly journals Solar hybrid air conditioning system to use in Iraq to save energy

2019 ◽  
Vol 124 ◽  
pp. 01024
Author(s):  
Y. V. Vankov ◽  
A. K. Al–Okbi ◽  
M. H. Hasanen
Keyword(s):  
Air Conditioning ◽  
Power Plants ◽  
Cooling System ◽  
Renewable Energy Sources ◽  
Electricity Consumption ◽  
Air Conditioners ◽  
Reduce Electricity Consumption ◽  
Central Air Conditioning ◽  
Save Energy ◽  
Air Conditioning Systems

The energy saving issues are becoming necessary worldwide, as excessive consumption of energy leads to the consumption of a larger amount of fuel, increases environmental pollution and negatively affects the ozone layer. In Iraq, in particular, the demand for central air conditioning systems and home air conditioners with high electrical capacity has become increasingly clear in the recent years. Air conditioning systems within residential and public buildings, as well as government facilities became a necessity for good internal comfort, which was driven by desertification, high temperature, air pollution and increased population, resulting in increased consumption of electric power and pressing of power plants. Aiming at usage of renewable energy sources, the proposed system uses solar collectors as auxiliary solar thermal compressors and integrate them with air conditioning systems. The proposed solution will increase the cooling system efficiency, reduce electricity consumption and pollution.

Installation Design and Energy Conservation Analysis of Floor Radiant Cooling/Heating System with Solar Energy

2012 ◽  
Vol 594-597 ◽  
pp. 2146-2153 ◽  
Author(s):  
Qi Fen Li ◽  
Tao Li ◽  
Wei Dong Sun ◽  
Zhi Tian Zhou ◽  
Cui Cui Pan ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Air Conditioning ◽  
Energy Savings ◽  
Heating System ◽  
High Energy ◽  
Primary Energy ◽  
Energy Saving Potential ◽  
Radiant Cooling ◽  
New Energy

How to reduce the energy consumption of air conditioning, to use new energy such as solar appropriately, and to achieve energy savings, are the problems must be treated in HVAC industry. Because of the high energy consumption of traditional air-conditioning and the need for reduction of emission, an air conditioning system (utilizing solar dehumidifying applied to heating/cooling radiant floor) is designed and installed in this paper. At the same time, as an example, the energy saving potential of system is analyzed. This type of heating/cooling radiant floor system is worth promoted if solve the dehumidification properly. By separating to deal with heat and moisture can reduce the energy-cost of traditional air-conditioning, and to achieve purposes of primary energy saving.

scholarly journals Reducing energy consumption of air-conditioning systems in moderate climates by applying indirect evaporative cooling

2018 ◽  
Vol 44 ◽  
pp. 00019
Author(s):  
Aleksandra Cichoń ◽  
Anna Pacak ◽  
Demis Pandelidis ◽  
Sergey Anisimov
Keyword(s):  
Air Conditioning ◽  
Heat Recovery ◽  
Energy Savings ◽  
Water Evaporation ◽  
Outdoor Air ◽  
Counter Flow ◽  
Additional Energy ◽  
Air Conditioning Systems ◽  
Vapour Compression ◽  
Mass Exchanger

This paper investigates the potential of applying an indirect evaporative cooler for heat recovery in air conditioning systems in moderate climates. The counter-flow indirect evaporative heat and mass exchanger is compared with commonly used recuperation unit in terms of achieved energy. The performance analysis of the indirect evaporative exchanger is carried out with original ε-NTU-model considering condensation from treated air. It was found that the indirect evaporative exchanger employed as a heat recovery device, allows to obtain higher performance than conventional recuperator. Additional energy savings potential is related with utilizing the potential of water evaporation to pre-cool the outdoor air. It is also stated that there is a high potential of reusing condensate that forms in product channels of the indirect evaporative exchanger and in the vapour-compression unit and delivering it to the working part of the indirect evaporative exchanger.

Investigation of the Down-Scaling Effects on the Low Swirl Burner and its Application to Microturbines

2018 ◽  
Author(s):  
Alex Frank ◽  
Peter Therkelsen ◽  
Miguel Sierra Aznar ◽  
Vi H. Rapp ◽  
Robert K. Cheng ◽  
...  
Keyword(s):  
Power Systems ◽  
Power Plants ◽  
Energy Savings ◽  
The United States ◽  
Primary Energy ◽  
Department Of Energy ◽  
Small Scale ◽  
United States Department ◽  
Scaling Effects ◽  
Swirl Burner

About 75% of the electric power generated by centralized power plants feeds the energy needs from the residential and commercial sectors. These power plants waste about 67% of primary energy as heat emitting 2 billion tons of CO2 per year in the process (∼ 38% of total US CO2 generated per year) [1]. A study conducted by the United States Department of Energy indicated that developing small-scale combined heat and power systems to serve the commercial and residential sectors could have a significant impact on both energy savings and CO2 emissions. However, systems of this scale historically suffer from low efficiencies for a variety of reasons. From a combustion perspective, at these small scales, few systems can achieve the balance between low emissions and high efficiencies due in part to the increasing sensitivity of the system to hydrodynamic and heat transfer effects. Addressing the hydrodynamic impact, the effects of downscaling on the flowfield evolution were studied on the low swirl burner (LSB) to understand if it could be adapted to systems at smaller scales. Utilizing particle image velocimetry (PIV), three different swirlers were studied ranging from 12 mm to 25.4 mm representing an output range of less than 1 kW to over 23 kW. Results have shown that the small-scale burners tested exhibited similar flowfield characteristics to their larger-scale counterparts in the non-reacting cases studied. Utilizing this data, as a proof of concept, a 14 mm diameter LSB with an output of 3.33 kW was developed for use in microturbine operating on a recuperated Brayton cycle. Emissions results from this burner proved the feasibility of the system at sufficiently lean mixtures. Furthermore, integration of the newly developed LSB into a can style combustor for a microturbine application was successfully completed and comfortably meet the stringent emissions targets. While the analysis of the non-reacting cases was successful, the reacting cases were less conclusive and further investigation is required to gain an understanding of the flowfield evolution which is the subject of future work.

Experimental Investigation of a Desiccant Wheel Cycle

2012 ◽  
Author(s):  
Ali Al-Alili ◽  
Yunho Hwang ◽  
Reinhard Radermacher
Keyword(s):  
Air Conditioning ◽  
Removal Rate ◽  
Dew Point ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Air Conditioners ◽  
Considerable Portion ◽  
Temperature Heat ◽  
Air Conditioning Systems ◽  
Desiccant Material

In hot and humid regions, removal of moisture from the air represents a considerable portion of the air conditioning load. Conventionally, air conditioning systems have to lower the air temperature below its dew point to accomplish dehumidification. Desiccant air conditioners offer a solution to meet the humidity and temperature requirements of buildings via decoupling latent and sensible loads. In this work, the performance of a new desiccant material is investigated experimentally. This desiccant material can be regenerated using a low temperature heat source, as low as 45°C. It also has a unique S-shape isotherm. The effects of the process air stream’s temperature and humidity, the regeneration temperature, the ventilation mass flow rate, and the desiccant wheel’s rotational speed on the cycle performance are investigated. ARI-humid conditions are used as a baseline and the moisture mass balance is maintained within 5%. The results are presented in terms of the moisture removal rate and latent coefficient of performance (COPlat). The results show a desiccant wheel’s COPlat higher than unity when it is coupled with an enthalpy wheel.

scholarly journals Improving efficiency and lowering operating costs of evaporative cooling

2021 ◽  
Vol 338 ◽  
pp. 01027
Author(s):  
Jan Taler ◽  
Bartosz Jagieła ◽  
Magdalena Jaremkiewicz
Keyword(s):  
Electricity Consumption ◽  
Open Circuit ◽  
Dew Point ◽  
Operating Costs ◽  
Water Evaporation ◽  
Total Water ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Adiabatic Cooling ◽  
Positive Effect

Cooling towers, or so-called evaporation towers, use the natural effect of water evaporation to dissipate heat in industrial and comfort installations. Water, until it changes its state of aggregation, from liquid to gas, consumes energy (2.257 kJ/kg). By consuming this energy, it lowers the air temperature to the wet-bulb temperature, thanks to which the medium can be cooled below the ambient temperature. Evaporative solutions are characterized by continuous water evaporation (approx. 1.5% of the total water flow) and low electricity consumption (high EER). Evaporative (adiabatic) cooling also has a positive effect on the reduction of electricity consumption of cooled machines. Lowering the relative humidity (RH) by approx. 2% lowers the wet-bulb temperature by approx. 0.5°C, which increases the efficiency of the tower, operating in an open circuit, expressed in kW, by approx. 5%, while reducing water consumption and treatment costs. The use of the M-Cycle (Maisotsenko cycle) to lower the temperature of the wet thermometer to the dew point temperature will reduce operating costs and increase the efficiency of cooled machines.

scholarly journals Design of a dew point evaporative cooler for buildings in Mediterranean climate

2019 ◽  
Vol 111 ◽  
pp. 02021
Author(s):  
Djallel Abada ◽  
Chadi Maalouf ◽  
Tala MOUSSA ◽  
Amel Ferial Boudjabi ◽  
Guillaume Polidori ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Mediterranean Climate ◽  
Electricity Consumption ◽  
Dew Point ◽  
Outdoor Air ◽  
New Techniques ◽  
Cooling Effectiveness ◽  
Crucial Problem ◽  
Cooling Technology ◽  
Evaporative Cooler

Refreshing air remains a crucial problem in warm climates where electricity consumption for air conditioning has become excessive and irrational for several years, notably in Algeria. Research in this field is increasingly oriented towards new techniques that can reduce costs and environmental impacts. Among these techniques, the evaporative dew point cooling technology is the most promising as it can cool outdoor air to temperatures below its wet bulb temperature. The aim of this work is to model and design a dew point cooler for french and algerian climates. This model is used to study the effect of the cooler parameters such as its length, water temperature and working air ratio on its cooling effectiveness and supply temperature.

scholarly journals Dynamic simulation of indirect air conditioning systems with optimized computational time

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.

Exergy Analysis of Energy Consumption for Central Air Conditioning System

2014 ◽  
Vol 628 ◽  
pp. 332-337
Author(s):  
Xiao Xia Xia ◽  
Nai Jun Zhou ◽  
Zhi Qi Wang
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Dew Point ◽  
Exergy Loss ◽  
Air Conditioning System ◽  
Air Cooler ◽  
Central Air Conditioning ◽  
Air Conditioning Systems

The energy consumption of several central air conditioning systems in summer was researched by the method of exergy analysis. Combined with actual example,the exergy loss of all the equipments and the exergy efficiency of three systems were calculated. The results show that the exergy efficiency of three systems is very low. Relatively speaking, the exergy efficiency of primary return air conditioning system with supplying air in dew point is highest. The equipment of highest exergy loss is air-conditioned room, while the exergy loss of surface air cooler is smallest. Based on this, several improvement measures were proposed to reduce exergy loss and improve exergy efficiency.

Effect of Different Italian Regulatory Frameworks on the Energetic Assessment of CHP Plants: A Comparative Design and Experimental Condition Analysis

2013 ◽  
Author(s):  
Marco Badami ◽  
Giacomo Bocci ◽  
Francesco Camillieri ◽  
Davide Pagliarulo ◽  
Armando Portoraro ◽  
...  
Keyword(s):  
Power Plants ◽  
Energy Savings ◽  
Primary Energy ◽  
Combined Heat And Power ◽  
Economic Benefits ◽  
Prime Mover ◽  
Design Data ◽  
European Directive ◽  
Regulatory Frameworks ◽  
Italian Legislation

Since a Combined Heat and Power (CHP) plant can offer high economic benefits when a certain energy savings value is obtained, it is very interesting to consider the requirements foreseen by legislation to meet this target. The paper deals with an energetic assessment of eleven industrial CHP power plants, based on different prime mover technologies installed and in operation in Italy. The analysis has been carried out considering not only the nominal design data of the plants, but also experimental ones, in order to highlight their real operational performances. The aim of the study was to compare the effects of two legislations on the calculation of the primary energy savings: the first is the Italian legislation that was in force when the power plants were designed, and the second is the current European Directive, which was issued a few years later when the plants were already in operation. The results of the study show as the subsidy mechanism introduced by the new legislation is stricter than the previous one, and could have a significant effect on the economic profitability of a cogeneration plant installation. More critical comments on the overall regulatory framework are presented in the paper.

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