Energy Consumption Load Research Articles

A new heating system based on coupled air source absorption heat pump for cold regions: Energy saving analysis

Energy consumption for heating and domestic hot water is very high. The heating system based on an air source absorption heat pump (ASAHP) had been assessed to have great energy saving potential. However, the single-stage ASAHP exhibits poor performance when the outdoor air temperature is very low. A double-stage coupled ASAHP is proposed to improve the energy-saving potential of single-stage ASAHP in cold regions. The heating capacity and primary energy efficiency (PEE) of the proposed system operated in both coupled mode and single-stage mode are simulated under various working conditions. The building load and primary energy consumption of different heating systems applied in cold regions are analyzed comparatively to investigate the energy-saving potential of the coupled ASAHP. Results show that the coupled ASAHP exhibits stable PEE and provides high heating capacity in very cold conditions. The energy-saving rate of the coupled ASAHP in all the typical cities is above 20%. In addition, the energy-saving potential of the single-stage ASAHP in severely cold areas can be improved obviously by coupled ASAHP, with an improvement of 7.73% in Harbin.

Passive energy recovery from natural ventilation air streams

Increasing levels of urbanisation and indoor air quality have led to enhanced research and development of sustainable technologies in buildings. This study investigated natural ventilation streams typically found in domestic buildings and used heat pipe technology to recover the energy from them. Computational Fluid Dynamics (CFD) based numerical code was used to predict the rate of heat transfer from a heat pipe heat exchanger model. The present numerical code was successfully validated against experimental data from literature. Pure water as a natural phase change material was employed to investigate the overall effectiveness of the heat pipe heat exchanger. Six models with varying vertical heights between the pipes were developed in order to investigate the optimum column pitch. A good correlation between the computational and analytical results was observed. The work focused on the vertical column height between the heat pipes and its impact on the overall rate of heat transfer, depicting an inverse relationship between the two parameters. The findings demonstrated the prospect for pre-cooling by 15.6°C and that a recovery of 3.3°C using this system which would assist in reducing energy consumption loads from the heating, ventilation and cooling sector, offering significant reduction in the carbon footprint of domestic buildings.

Impact of Pulp Consistency on Refining Process Conducted under Constant Intensity Determined by SEL and SEC Factors

Specific Edge Load (SEL) and Specific Energy Consumption (SEC) are nowadays the most popular parameters for defining the intensity of pulp refining. As a result, these factors are widely used in industrial practice. The purpose of this research was to determine limitations connected with use of these parameters during bleached kraft pulp refining. Performed tests showed that, despite keeping the SEL and SEC at constant level, changes of pulp refiner consistency always modified the character of the refining process. Obtained results showed that neither SEL nor SEC are fully reliable parameters to describe and to control the refining process.

Hockey Experimental Study on the Characteristics of Different Exercise Load

As times and technology advances, hockey movement with the hockey field of artificial ground improvement, hockey rod material improvement, rules changes and so on , the hockey players ' physical fitness and technique also had higher requirements. Research field hockey shooting technology, passing and catching skills, dribbling, sports competitions and small unit in different load characteristics of movement become hot. This research through the different physiological function load index, quantified shot technology, catch technology, dribbling technical movement, sports technical movement unit and small site game load related research, the results show that the movement technology action unit and small site game heart rate load is obviously higher than that of the total playing time and intermittent playing time heart rate load and pure game time load no significant difference; Different physiological function and energy consumption load index difference comparison shows, a single technical action of load between no significant difference, small site game load is obviously higher than that of the motion unit load.

The Measured Impact of Vehicle Mass on Road Load Forces and Energy Consumption for a BEV, HEV, and ICE Vehicle

The U.S. Department of Energy’s Office of Energy Efficiency & Renewable Energy initiated a study that conducted coastdown testing and chassis dynamometer testing of three vehicles, each at multiple test weights, in an effort to determine the impact of a vehicle’s mass on road load force and energy consumption. The testing and analysis also investigated the sensitivity of the vehicle’s powertrain architecture (i.e., conventional internal combustion

Simplified optimization method for preliminary design of HVAC system and real building application

HVAC systems (heating, ventilation, and air conditioning) are recognized as the greatest energy consumers in commercial and institutional buildings. Generally, designers use common sense, historical data, and subjective experience in designing these systems; this includes the number of systems chosen and the grouping of the zones served by these systems. HVAC energy efficiency is not an easily calculable criterion during the selection of these systems; usually the first selection criterion is the weakest investment cost. In this article, we present a simplified optimization method for preliminary design of HVAC system using the zones’ daily profile loads. A global load ratio is applied as an optimization function. The global load ratio represents the relationship between the system's real load and its possible maximum load for a given period. The variables for the optimization problem are: (i) grouping of the zones served by the systems and (ii) number of systems serving the building. Type of system was preselected for the present study, but this could also serve as an optimization variable. The correlations between global load ratio and energy consumption were shown using an office building. Then, this method was applied on an existing institutional building and compared with the detailed optimization method. In the second method, the HVAC energy consumption, calculated using DOE-2 software, was used as the optimization function. The comparison made among the existing, reference, and optimized buildings (all sharing the same constraints) have yielded significant energy savings for HVAC energy consumption. A life cycle cost analysis has also been done to estimate savings in terms of investment, operation and maintenance costs. These savings depend upon building configuration, the constraints imposed, the types of HVAC systems selected, and the control strategies for these systems.

Illumination control of LED systems based on neural network model and energy optimization algorithm

Lighting constitutes a large proportion of the main energy consumption loads of a building; energy-efficient lighting control is an important topic to be addressed in achieving green building requirement. Within a building, huge amount of lights are being deployed in a distributed manner which poses great challenge in achieving energy saving and personalized lighting control. In this paper, the objective is to satisfy table illumination preference of each office user while minimize energy consumption of the overall lighting system by optimizing the illumination levels of the distributed luminaires. A holistic and scalable neural network model is developed to represent the complex relationship between dimming levels of luminaires and measured illuminance on the table. Based on the developed model, a lighting energy optimization algorithm is proposed to achieve energy saving while having personalized lighting control. The proposed model can serve as a base model for the improved artificial light and even daylight control system in the future study.

전기적 열제어 시스템을 사용한 에너지 소비량 감소에 관한 연구

Most of steam power plant in Korea are heating the feed water system to prevent freezing water flowing in the pipe in winter time. The heating system is operated whenever the ambient temperature around the power plant area below 5 degree Centigrade. But this kind of heat supplying system cause a lot of energy consuming. If we think about the method that the temperature of the each pipe is controled by attaching the temperature measuring sensor like RTD sensor and heat is supplied only when the outer surface temperature of the pipe is under 5 degree Centigrade, then we can save a plenty of energy. In this study, the computer program package for simulation is used to compare the energy consumption load of both systems. Energy saving rate is calculated for the location of Youngweol area using the data of weather station in winter season, especially the January' severe weather data is analyzed for comparison. Various convection heat transfer coefficients for the ambient air and the flowing water inside the pipe was used for the accurate calculation. And also the various initial flowing water temperature was used for the system. Steady state analysis is done previously to approximate the result before the simulation. The result shows that the temperature control system using RTD sensor represents the high energy saving effect which is more than 90% of energy saving rate. Even in the severe January weather condition, the energy saving rate is almost 60%.

Design of an energy‐efficient cross‐layer protocol for mobile ad hoc networks

Reducing energy consumption for data transmissions and prolonging network lifetime are crucial in the design of energy-efficient routing protocols. The proportion of successful data transmissions is significant for the reduction of data transmission and traffic load energy consumption, although the energy remaining in node is important for prolonging network lifetime. In this study, the authors propose an energy-efficient cross-layer design for the network layer and medium access control (MAC) layer that reduces energy consumption and prolongs network lifetime. In the network layer, a minimum transmission energy consumption (MTEC) routing protocol is proposed for selecting the MTEC path for data transmission, based on the proportion of successful data transmissions, the number of channel events, the remaining node energy of nodes and the traffic load of nodes. The authors design an adaptive contention window (ACW) for the MAC layer that provides nodes with high successful transmission rates with greater opportunity for contending for a channel to save energy. They used simulations to compare the proposed cross-layer design (MTEC with ACW) with related protocols, including dynamic source routing, traffic-size aware and the Varaprasad routing protocol. The simulation results showed that the proposed cross-layer design (MTEC with ACW) provided better packet delivery rate and throughput than existing protocols. MTEC with ACW also exhibited lower-energy consumption during data transmission and a higher network lifetime than existing protocols.

Heat Pump Technology Applies on Air-conditioners Impact on Electric Power

In recent years, power grid has been experienced in difficult times that there is a shortage of demand load among market, and more and more black out exited that bothered residents’ normal life. With the increment of energy consumption and power load, this problem will be more serious without any feasible solutions. Besides, the air conditioning system is the largest residential energy consumer. In this report, a GSHP air conditioning system has been illustrated and compared with the conventional air conditioning system currently used in Chengdu, Sichuan province, China. The benefits of using the GSHP system are not only on cost saving, but also energy saving and eco-friendly.

A Strategy for Avoiding Energy Holes Based on Data Fusion in Wireless Sensor Network

Energy holes problem is one of key issues for wireless sensor networks (WSN). At present, the resolved strategies mainly focus on non-uniform node distribution and adjusting transmission power. However, some costs are incurred by non-uniform node distribution. With the number of nodes increasing, the total number of nodes grows exponentially, and there is a need to improve physical conditions when we increase transmission power significantly in large class of network model; To overcome the limitation, we propose the strategy of data fusion, whose reason is that it is not limited to the size of network, and does not need complicated physical conditions. In this paper, we first establish a network model Multiple-Layer and Multiple-Clusters in corona model (MLMC) to analyze the loading energy consumption. What’s more, we consider energy consumption when network is constructed. Furthermore, we fully introduce our strategy of data fusion, and prove two theorems to balance energy consumption for resolving energy holes problem. Finally, we compare and analyze the total energy consumption and network lifetime between before and after data fusion. The experimental results demonstrate the performance advantages of our approach. The best is to read these instructions and follow the outline of this text.

Methodology for generating electric load profiles for sizing an electric energy generation system

Electric energy prices in Brazil are higher during 3h of peak consumption on working days; however, consumers could use a generator system for partially reducing the electricity costs from utility company during peak hours. The process of sizing a generator system begins developing the so called load capacity curve, using acquired building electricity consumption data. The local utility company supplies this data only for the last month of operation; consequently, data are unavailable for the rest of the year. In order to overcome the difficulty, this paper develops two methodologies to estimate the curve for every month of the year. The first one uses the frequency of occurrence of the measured values of the load power in each bin and the last one the monthly values of load power and energy consumption, as supplied by the local utility monthly bills. In order to validate the methodologies, monthly utility bills and consumption data of electric energy measured at Pontifical Catholic University of Rio de Janeiro, every 15min over a four year period, have been used. Finally a generator system was sized, minimizing the electrical energy cost supplied by it, when the generator meets partially the building load.

Measured end-use electric load profiles for 12 Canadian houses at high temporal resolution

The electricity drawn by appliances and lighting represents a significant fraction of the total energy used in residential buildings. As construction techniques improve and as building regulations become more stringent, it is expected that the relative significance of these non-HVAC electrical loads will grow. Not only is the annual energy consumption of non-HVAC electrical loads of growing importance, their temporal distribution influences the operation of energy conversion equipment within the building and in the electrical supply network. This work provides new measured data on the electrical consumption of a sample of 12 Canadian houses. Measurements at 1-min intervals were taken of whole-house electricity draws, as well as the draws of individual devices, including the furnace, air-conditioner, range/cooker, clothes dryer, dishwasher, and domestic hot water heater. The annual consumption patterns of the 12 houses were found to range widely. Furthermore, daily variations in the temporal distribution of electrical loads of each house were found to be significant. The probability distribution of some of the measured data was compared with previously developed synthetically derived non-HVAC electric load profiles, and it was found that the latter do not adequately capture either the temporal variability nor the variation between households observed in the measurements.

Investigation on air-conditioning load profile and energy consumption of desiccant cooling system for commercial buildings in Hong Kong

In Hong Kong, conventional air-conditioning (AC) systems cause a high energy consumption and poor indoor thermal comfort. This paper investigated the AC load profiles of three typical local commercial buildings, i.e. office, hotel and retail, and examined the energy consumption of liquid desiccant cooling system (LDCS) for these buildings. Simulation results showed that the cooling load contributed to more than 98% of total annual load, with high latent load proportion from March to September. The high reheating ratio, i.e. from 60% to 90%, is found to be the main reason for the poor thermal comfort. Therefore, the LDCS which could handle sensible and latent loads separately was proposed. However, the electricity-driven LDCS was found not suitable for local commercial buildings. significant energy saving could be achieved by the solar-assisted LDCS system with thermal storage, when the installation area for solar collectors is larger than the minimum required one, i.e. 9.7m2/(kWm−2) for office and 12.7m2/(kWm−2) for hotel buildings. Energy saving of different system types with different installation areas was also studied. The solar-assisted LDCS shows more energy saving in winter but less in summer. Results and conclusions can be useful for researchers and local engineers.

두개의 제어기를 사용한 건물 내부의 온도변화와 에너지소비량을 계산하기 위한 해석적 연구

Four different buildings having various wall construction are analyzed for the effect of wall mass on the thermal performance and inside building air and wall temperature transient and also for calculating the energy consumption load. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one-dimensional, linear, partial differential equations is obtained using the Laplace transform method, Bromwich and modified Bromwich contour method. A simple dynamic model using steady state analysis as simplified methods is developed and results of energy consumption loads are compared with results obtained using the analytical solution. Typical Meteorological Year data are processed to yield hourly average monthly values. This study is conducted using weather data from two different locations in Korea: Daegu having severe weather in summer and winter and Jeju having mild weather almost all year round. There is a significant wall mass effect on the thermal performance of a building in mild weather condition. Buildings of heavyweight construction with insulation show the highest comfort level in mild weather condition. A proportional controller provides the higher comfort level in comparison with buildings using on-off controller. The steady state analysis gives an accurate estimate of energy load for all types of construction. Finally, it appears that both mass and wall insulation are important factors in the thermal performance of buildings, but their relative merits should be decided in each building by a strict analysis of the building layout, weather conditions and site condition.

Optimization concepts in district energy design and management – A case study

The integration of optimization techniques in building and district energy design constitute an essential tool for reducing the global impact of energy services. Appropriate dynamic energy management systems must be employed too in order to maintain a high level of performance in the operational phase and to obtain better system knowledge. Therefore, in the strategic energy planning of districts, it is necessary to embody the main concepts of Smart Grid and virtual power plants frameworks. In the research presented, the preliminary results from a case study are illustrated with a reflection on energy consumption subdivision and load profiles for the sizing and operational strategy definition of distributed generation systems.

Improving the Model for Energy Consumption Load Demand Forecasting

Improving the Model for Energy Consumption Load Demand Forecasting

A method for determining the effective longwave radiative properties of pleated draperies

Draperies, attached to fenestration, offer a cost-effective strategy in controlling solar gain since draperies have the potential to reduce building peak load and annual energy consumption. The performance of a drapery is dependent on its solar optical and longwave radiative properties. The current study considers the determination of spatially averaged (effective) longwave radiative properties of draperies. As a first step, the longwave properties of fabrics were obtained by taking measurements with an infrared reflectometer using two backing surfaces. The measurement results enabled simple equations to be developed relating emittance and longwave transmittance to openness, emittance, and longwave transmittance of the fabric structure. In turn, the effective longwave properties of a pleated drapery are modeled using a net radiation scheme with fabric longwave properties as input. The model approximates a drapery as a series of uniformly arranged rectangular pleats. The effective longwave properties of the pleated drapery are calculated by considering an enclosure that is representative of the entire series of pleats. The longwave properties of the drapery are functions of only pleat geometry and openness of the fabric. The model compares favorably with expected trends and limits. The effect of pleating (folding ratio) is also examined.

Off-normal solar optical property measurements using an integrating sphere

Shading devices attached to windows can be used to control solar gain and hence reduce building peak load and annual energy consumption. The performance of a shading device in this regard is strongly dependent on its solar optical properties. The current study discusses a unique measurement technique that was used to obtain off-normal solar optical properties of flat shading materials. The off-normal properties were needed in order to develop solar optical property models both for shading materials and shading devices. These models provide useful input to building peak load calculation and annual energy simulation tools. Special sample holders were designed and fabricated to facilitate measurements using a commercial spectrophotometer with integrating sphere attachment. A combination of theory and companion tests were used to confirm the validity of the approach.

Electric Thermal Storage Option for Nova Scotia Power Customers: A Case Study of a Typical Electrically Heated Nova Scotia House

ABSTRACT Nova Scotia Power (NS Power) offers an incentive to the owners of electrically heated houses in Nova Scotia to switch from conventional electric baseboard heaters to electric thermal storage (ETS) systems and enjoy the rebated time-of-day (TOD) electricity rates. For this study, a statistically representative, electrically heated, existing Nova Scotia house was modeled in the building energy simulation software ESP-r to estimate its peak heating load and hourly heating energy consumption for an entire year. Based on the ESP-r simulation results, the ETS system was sized for the house, and the energy cost saving realized with this system was estimated. It was found that, compared to conventional electric baseboard heating system, the ETS heating system can save 41–48% in the heating cost on an annual basis, yielding a simple-payback (SPB) period for this retrofit of less than eight years.