Optimizing the pad thickness of evaporative air-cooled chiller for maximum energy saving

2013 ◽  
Vol 61 ◽  
pp. 146-152 ◽  
Author(s):  
Xiaoli Hao ◽  
Cangzhou Zhu ◽  
Yaolin Lin ◽  
Haiqiao Wang ◽  
Guoqiang Zhang ◽  
...  
Keyword(s):  
Energy Saving ◽  
Maximum Energy

Energy-saving design of variable-displacement bi-directional pump-controlled electrohydraulic system

2020 ◽  
pp. 095965182097389
Author(s):  
Samir Kumar Hati ◽  
Nimai Pada Mandal ◽  
Dipankar Sanyal
Keyword(s):  
Energy Saving ◽  
Absolute Error ◽  
Fast Response ◽  
Maximum Energy ◽  
Radial Clearance ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Axial Piston

Losses in control valves drag down the average overall efficiency of electrohydraulic systems to only about 22% from nearly 75% for standard pump-motor sets. For achieving higher energy efficiency in slower systems, direct pump control replacing fast-response valve control is being put in place through variable-speed motors. Despite the promise of a quicker response, displacement control of pumps has seen slower progress for exhibiting undesired oscillation with respect to the demand in some situations. Hence, a mechatronic simulation-based design is taken up here for a variable-displacement pump–controlled system directly feeding a double-acting single-rod cylinder. The most significant innovation centers on designing an axial-piston pump with an electrohydraulic compensator for bi-directional swashing. An accumulator is conceived to handle the flow difference in the two sides across the load piston. A solenoid-driven sequence valve with P control is proposed for charging the accumulator along with setting its initial gas pressure by a feedforward design. Simple proportional–integral–derivative control of the compensator valve is considered in this exploratory study. Appropriate setting of the gains and critical sizing of the compensator has been obtained through a detailed parametric study aiming low integral absolute error. A notable finding of the simulation is the achievement of the concurrent minimum integral absolute error of 3.8 mm s and the maximum energy saving of 516 kJ with respect to a fixed-displacement pump. This is predicted for the combination of the circumferential port width of 2 mm for the compensator valve and the radial clearance of 40 µm between each compensator cylinder and the paired piston.

Energy-Saving Evaluation of SOFC Cogeneration Systems With Solar Cell and Battery

2014 ◽  
Vol 11 (6) ◽  
Author(s):  
Akira Yoshida ◽  
Koichi Ito ◽  
Yoshiharu Amano
Keyword(s):  
Solar Cell ◽  
Energy Saving ◽  
Energy Supply ◽  
Energy Savings ◽  
Optimization Theory ◽  
Maximum Energy ◽  
Planning Problem ◽  
Energy Supply System ◽  
Energy Demands ◽  
Cogeneration System

The purpose of this study is to evaluate the maximum energy-saving potential of residential energy supply systems consisting of a solid oxide fuel cell (SOFC) cogeneration system (CGS) combined with a solar cell (SC) and a battery (BT), compared with a reference system (RS). This study applies an optimization theory into an operational planning problem to measure actual energy demands over the course of 1 year. Eight different types of energy supply system were compared with each other by changing the components of the SOFC-CGS, SC, BT, and RS. Meaningful numerical results are obtained, indicating the maximum potential energy savings.

scholarly journals Utilizing the solar thermal ice storage system in improving the energy, exergy, economic and environmental assessment of conventional air conditioning system

2021 ◽  
Author(s):  
Mohamed Elhelw ◽  
Wael M. El-Maghlany ◽  
Mohamed Shawky Ismail ‎
Keyword(s):  
Energy Saving ◽  
Air Conditioning ◽  
Storage System ◽  
Water System ◽  
Maximum Energy ◽  
Ice Storage ◽  
Air Conditioning System ◽  
Air System ◽  
Alexandria City ◽  
Air Conditioning Systems

Abstract This paper introduces novel modification for conventional air conditioning systems through utilizing a thermal ice storage system integrated with solar panels. Alexandria and Aswan, cities in Egypt, are chosen to represent two climates for hot-humid and hot-dry climates respectively. The governing equations for both heat and mass transfer are theoretically solved. Exergy analysis is performed for the proposed solar-ice thermal storage system via determining exergy destruction on ice and solar components as well as the total destruction based on transient analysis. This study was carried out on two common types of air conditioning systems, an air handling unit and fan coil unit. Results showed that, solar-ice storage system is more effective approach in hot-humid climate than hot-dry climate and more efficient with all-water air conditioning system than with all-air conditioning system. The maximum energy saving is 205.16 GJ having a percent of 27.5% in August for all water system in case of Alexandria city and 224.67 GJ with a percent of 25.38% in August for all-water system in case of Aswan city. All air system simulation showed maximum energy saving of 175.05 GJ with a percent of 18.13 % in case of August for Alexandria and 175.45 GJ having a percentage of 17.43% in case of Aswan in August. Moreover, the all-water system achieved a reduction in CO2 emissions by 467 tons/year in Aswan city and 390 tons/year in case of Alexandria city. While these reductions decrease to be 435 and 353 tons/year when the all-air system used for the same two cities.

A Parametric Study on Exterior Insulation Systems and Heat Reflective Paints for Energy Efficiency in Buildings

2015 ◽  
Vol 650 ◽  
pp. 71-81
Author(s):  
Biman Ghosh
Keyword(s):  
Energy Saving ◽  
Developed Countries ◽  
Maximum Energy ◽  
Building Envelope ◽  
Maximum Temperature ◽  
Test Results ◽  
Maximum Temperature Difference ◽  
New Techniques ◽  
Insulation Systems ◽  
Actual Field

Buildings are responsible for at least 40% of the used energy in most of the countries and the figure is rising as the construction booms. But pace of energy saving in building is much lower in India as compared to developed countries. So, there is an immediate need to open up new techniques to address the issue and also progress in the area of actual implementation should be accelerated immediately because both knowledge and techniques are available today to slash the energy usage in a building.Our focus is mainly on the modification of building envelope to reduce the energy used for cooling in A/C building and to reduce the temperature of the interior of non-A/C building.Berger has developed different systems such as EIFS for wall, Roof insulation and Heat reflecting paint for both wall & roof. The efficiency of these systems in terms of energy saving and cooling has been tested at Howrah and also has been tested by CBRI at Roorkee, through actual field study for two years. The test results revealed that the maximum energy saving of 32.33% can be achieved for A/C building. For non A/C building, maximum temperature difference of 6.4°C between outdoor and indoor air of the room can be achieved.

Waste-Heat Recovery in Batch Processs Using Heat Storage

1995 ◽  
Vol 117 (2) ◽  
pp. 142-149 ◽  
Author(s):  
S. Stoltze ◽  
J. Mikkelsen ◽  
B. Lorentzen ◽  
P. M. Peterson ◽  
B. Qvale
Keyword(s):  
Energy Saving ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Heat Storage ◽  
Waste Heat ◽  
Maximum Energy ◽  
Point Method ◽  
Batch Processes ◽  
Storage Tanks ◽  
Pinch Point

The waste-heat recovery in batch processes has been studied using the pinch-point method. The aim of the work has been to investigate theoretical and practical approaches to the design of heat-exchanger networks, including heat storage, for waste-heat recovery in batch processes. The study is limited to the incorporation of energy-storage systems based on fixed-temperature variable-mass stores. The background for preferring this to the alternatives (variable-temperature fixed-mass and constant-mass constant-temperature (latent-heat) stores) is given. It is shown that the maximum energy-saving targets as calculated by the pinch-point method (time average model, TAM) can be achieved by locating energy stores at either end of each process stream. This theoretically large number of heat-storage tanks (twice the number of process streams) can be reduced to just a few tanks. A simple procedure for determining a number of heat-storage tanks sufficient to achieve the maximum energy-saving targets as calculated by the pinch-point method is described. This procedure relies on combinatorial considerations, and could therefore be labeled the “combinatorial method” for incorporation of heat storage in heat-exchanger networks. Qualitative arguments justifying the procedure are presented. For simple systems, waste-heat recovery systems with only three heat-storage temperatures (a hot storage, a cold storage, and a heat store at the pinch temperature) often can achieve the maximum energy-saving targets. Through case studies, six of which are presented, it is found that a theoretically large number of heat-storage tanks (twice the number of process streams) can be reduced to just a few tanks. The description of these six cases is intended to be sufficiently detailed to serve as benchmark cases for development of alternative methods.

scholarly journals Verification of IRRILAB Software Application for the Hydraulic Design of a Micro-Irrigation System by Using IRRIPRO for an Apple Farm in Sicily

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 694
Author(s):  
Giorgio Baiamonte ◽  
Pietro Di Dio ◽  
Mustafa Elfahl
Keyword(s):  
Energy Saving ◽  
Numerical Solutions ◽  
Irrigation System ◽  
Maximum Energy ◽  
Software Application ◽  
Software Applications ◽  
First Choice ◽  
One Step ◽  
Micro Irrigation ◽  
Save Energy

In recent years, many studies have been performed to develop simple and accurate methods to design micro-irrigation systems. However, most of these studies are based on numerical solutions that require a high number of iterations and attempts, without ensuring to maximize water use efficiency and energy-saving. Recently, the IRRILAB software, which is based on an analytical approach to optimally design rectangular micro-irrigation units, has been developed, providing the solution corresponding to the maximum energy-saving condition, for any slope of the laterals and of the manifold. One IRRILAB limitation is that, according to its theoretical basis, the rectangular planform geometry and uniform slope of the laterals and of the manifold are required. On the contrary, IRRIPRO software, which is based on the traditional numerical solution, does not have the aforementioned limitations, but requires an important number of attempts, especially when common emitters are used. In this study, the results of a joint use of IRRILAB and IRRIPRO software applications are illustrated, towards the aim to verify the IRRILAB performance in a large number of micro-irrigation sectors belonging to a Sicilian apple farm, which is characterized by a high irregular topography, thus it is suitable for the purpose of this study. First, only five irrigation sectors, for the actual subdivisions of the farm, were considered, showing limited reasonable IRRILAB results. Dividing the farm into a higher number of sectors so as to provide a better uniformity in planform geometry and slope revealed that IRRILAB results improved in terms of emission uniformity and energy consumption, as verified by IRRIPRO applications. The energy-saving provided by IRRILAB (in one step) with respect to that by IRRIPRO (by attempts) resulted higher for common emitters (CEs) (−15% for five sectors and −9% for nine sectors) than for pressure compensating emitters (PCEs) (−7% for five sectors and −6% for nine sectors). In absolute terms, the energy is greater for five-sector subdivision than for nine-sector subdivision. For both software, the use of PCEs always required less energy than CEs, because of the higher range of pressure compensating of PCEs than CEs. However, PCEs are characterized by less durability and by a higher manufacturing variation coefficient, thus they should not be the first choice. In conclusion, IRRILAB software could be recommended because it is easy to use, making it possible to save energy, especially when sectors are almost rectangular and uniform in slopes.

scholarly journals Analysis of the energy-saving potential for heating of double skin glass-glass façades

2020 ◽  
Author(s):  
Víctor Diez-Martínez ◽  
Roberto Getino-de-la-Mano ◽  
José Luis Falagán-Cavero ◽  
David Borge-Diez
Keyword(s):  
Energy Saving ◽  
Linear Relationship ◽  
Energy Savings ◽  
Heated Surface ◽  
Maximum Energy ◽  
Solar Irradiation ◽  
Outdoor Temperature ◽  
Annual Average ◽  
Energy Flows ◽  
Double Skin

The energy flows of the double skin, glass-glass façades have been analysed, establishing a mathematical model to determine the energy savings provided by this construction solution in 10 cities in Spain. It has been found that the two climatological variables that most influence energy savings are outdoor temperature, as it is directly related to the demand for heating, and solar irradiation, as it is the source of energy from which savings are extracted. Energy savings in winter vary between 11.1% and 20.5%, depending on the weather. A linear relationship between the annual average outdoor temperature and the useful energy provided by the double- skin façade has been determined. It was verified that the maximum energy saving occurs when the façade is offset a few degrees to the east from the pure south orientation. It deviates further east, the higher the annual average temperature. A linear relationship has been established between the outside temperature and the azimuth of the façade with which the maximum energy saving occurs. To obtain savings percentages greater than 20%, the ratio between the double-skin façade surface and the total heated surface of the building must be less than 7.

Energy Savings Opportunities of an Integrated Facility and Production Line

2013 ◽  
Author(s):  
Michael P. Brundage ◽  
Qing Chang ◽  
Dongmei Chen ◽  
Victor Yu
Keyword(s):  
Energy Saving ◽  
Production Line ◽  
Energy Demand ◽  
Energy Savings ◽  
Cost Savings ◽  
Maximum Energy ◽  
Manufacturing Plant ◽  
Hvac System ◽  
Modern Manufacturing ◽  
Integrated Facility

In modern manufacturing facilities there are many energy saving opportunities (ESO) that are wasted by the lack of integration between the facility and the production system. This paper deals with an integrated production line and the heating, ventilation, and air conditioning (HVAC) system and explores the different energy saving opportunities of the two largest energy consumers in the manufacturing plant. The energy opportunity window of each machine is utilized to allow for energy savings for the production line without throughput loss on the floor. This opportunity window is synced with the peak periods of energy demand for the energy demand of the HVAC system. The integration of these two systems allows for the maximum energy cost savings. These systems are modeled and tested using simulation case studies.

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