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The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

At the viewpoint of energy saving and the increasing needs of seaside leisure activities in Korea, floating architecture is recently to be focused on, but it is in the early stage of technological development. Considering the features of floating structures that can float and move on sea and/or river, this study proposes Single-U type Sea Water Heat Exchanger (SWHEx) and Spring type SWHEx that installed into or outside the submerged concrete structure of pontoon, respectively. As the results from CFD and mock-up tests, it is found out that the mean temperature difference is 3°C between the inlet and outlet temperatures of working fluid which flows inside the Single-U type SWHEx and 1.5°C for Spring type SWHEx. Also it is clear that the heat exchange performance of Single-U type SWHEx is better than Spring type.

With the purpose of clarifying the energy-saving influencing factors of the participants in the construction project, qualitative analysis and scientific measurement analysis were combined in this paper to define and identify the energy-saving influencing factors of the construction project lifecycle. First, a qualitative analysis of the research literature of the natural science index (SCI) and social science citation index (SSCI) databases was conducted through a combination of literature analysis and expert interviews, constructing a list of the energy-saving influencing factors in the lifecycle of construction projects. Second, the knowledge map of the energy-saving research literature of construction projects in the past 20 years from the Web of Science (WOS) database was drawn through Citespace. Then the hotspots of energy-saving research in international construction projects were identified through keyword co-occurrence map as energy saving, energy efficiency, and energy consumption. The main research subjects were divided into four categories: energy-saving management and incentive policies, project users’ energy-saving behaviors and awareness, various energy-saving new materials and technologies, and energy-saving management and control at the operation and maintenance stage. Next, nine main clusters on energy-saving research were identified through cluster analysis, mainly distributed in various energy-saving technology research, energy-saving behavior and power research of owners and residents, policy and regulation research, and energy-saving management and control research in the operation and maintenance stage. Finally, the knowledge mapping analysis results were classified and defined according to the action scope of each stage of the construction project, and the identification of the energy-saving influencing factors in the construction project lifecycle was completed.

In this paper, a high energy saving digital-to-analog converter (DAC) switching scheme with common-mode voltage variation in 1LSB is proposed for successive approximation register (SAR) analog-to-digital converters (ADCs). Based on the third reference ($V_{\mathrm{\text{cm}}}$), split-capacitor technique and complementary switching method, the proposed switching scheme achieves a 99.6% switching energy reduction and a 75% area reduction compared to the conventional architecture, furthermore, the common-mode voltage varies only 1LSB during a conversion cycle.

As an important component of computer system, GPU has been used more widely in the system under the support of general computing. In addition to focusing on its performance, the issues of its energy consumption and environmental problem have gradually attracted the concerns of researchers, computer architects, and developers. Current researches only consider single-task scheduling for saving energy, lacking the focus on energy saving from scheduling the overall tasks. In view of the shortcomings of current researches, we propose a METS (Minimizing Execution Time Slot) approach to reduce energy by rationally allocating the tasks across GPUs. It first collects the number of tasks and the corresponding estimated performance information. Next, it decides whether to turn the problem into a 0–1 knapsack problem or to use FIFO method based on the number of tasks. Then, we conduct our experiment on typical platform to verify our proposed approach. The experimental results show that METS can save on average 8.43% of energy when compared with the existing approaches. This shows that the proposed METS method is effective, reasonable and feasible.

In elastic clusters, the service resources (or called “resources” for short) can be dynamically scaled, thus providing opportunities to cut down the energy cost of redundant resources. Generally, taking into account the Quality of Service (QoS) of clusters, resources are carefully scaled according to specific hints which are some features of system status. However, when the Service Quality Requirement (SQR) is referred to the response time of requests, some widely used features cannot well reflect the status of the QoS. Consequently, the QoS cannot be well maintained, and the energy-saving efficiency is unsatisfactory. In this paper, we indicate that under such SQR, the outstanding hint for resource scaling is the response time of requests. Accordingly, we propose a resource scaling method which scales resources leveraging an elaborate Hint of Response time (HR). More specifically, HR is credible to foresee future QoS, and our method extracts HR by tracking and making analysis on the waiting requests in each server. Moreover, when resource scaling operation is performed, our method can estimate how many resources are suitable for current workloads with a good accuracy. Thereby, our method can timely and directly scale resources to the suitable amount, thus can significantly reduce the time delay of re-matching resources. Finally, our method can significantly promote cluster performance on both the QoS and the energy-saving efficiency.

This paper proposes a deduplication-based mixed page strategy, called DM-Pages, to improve the energy efficiency of disk storage systems and the cache performance. DM-Pages strives to improve the cache hit rate, simultaneously reduce the number of power-state transitions of a disk storage system and keep it in a low-power state as long as possible. DM-Pages deploys three innovative techniques. It adjusts the size of huge pages dynamically to maximize the cache hit rate. Meantime, content-aware deduplication is applied to eliminate redundant cache pages, targeting to enhance cache utilization. In addition, DM-Pages incorporates a mixed page mechanism into disk energy management to save energy. Our experimental results show that DM-Pages significantly improves the energy efficiency of disk storage systems and achieves a high cache hit rate. In particular, compared with traditional disk storage systems, DM-Pages conserves 6.59 times energy and improves the cache hit rate up to 3.36 times.

In this paper, we propose an approach solving the holes problem in Wireless Sensor Networks (WSNs) based on Khalimsky k-Clustering and data routing protocol (MDKC). The aim of this solution is to establish optimized data routing paths between isolated nodes/clusters and the Sink in noisy environment with the presence of obstacles. This approach is an improvement of a previous work deploying stationary WSN not dealing with the problem of “holes”. At first, the MDKC algorithm divides the WSN into k-hop $(k\ge 2)$ compact dynamic clusters. For each cluster, a node is elected cluster-head in its k-neighborhood according to some criteria such as the remaining energy, the k-degree and the communication probability average. Then, some nodes are selected as Khalimsky anchors to optimize the intra-cluster data routing process. The Khalimsky anchors at the border layers ensure the inter-cluster data routing between adjacent clusters. In the next phase of MDKC, Mobile Collectors (MCs) are used for data collecting and relaying from isolated nodes/clusters to the connected Khalimsky’s nodes. The simulation results prove that MDKC minimizes the energy consumption and improves the connectivity rate between sensors and the delivery rate compared to some existing approaches.

Volatile organic compounds are the major concern with formaldehyde being the dominant indoor air pollutant. Exploring advanced catalysts towards energy-saving formaldehyde oxidation catalysts is the key to mitigate the risks from indoor air. This review summarizes the recent progress on enhancing oxidation of formaldehyde by tailoring the structure, morphology, surface, interface and external field of catalysts. The modification strategy of various catalysts is discussed with focus on mass transfer enhancement, surface manipulation, interface engineering and environment regulation. Future researches to address the remaining challenges on formaldehyde oxidation are also proposed, which are expected to inspire further sparkling ideas for development of energy-saving systems toward efficient removal of formaldehyde.

From 21st century, it is hard for traditional storage and algorithm to provide service with high quality because of big data of communication which grows rapidly. Thus, cloud computing technology with relatively low cost of hardware facilities is created. However, to guarantee the quality of service in the situation of the rapid growth of data volume, the energy consumption cost of cloud computing begins to exceed the hardware cost. In order to solve the problems mentioned above, this study briefly introduced the virtual machine and its energy consumption model in the mobile cloud environment, introduced the basic principle of the virtual machine migration strategy based on the artificial bee colony algorithm and then simulated the performance of processing strategy to big data of communication based on artificial bee colony algorithm in mobile cloud computing environment by CloudSim3.0 software, which was compared with the performance of two algorithms, resource management (RM) and genetic algorithm (GA). The results showed that the power consumption of the migration strategy based on the artificial bee colony algorithm was lower than the other two strategies, and there were fewer failed virtual machines under the same number of requests, which meant that the service quality was higher.

Commercial multiple evaporators variable refrigerant flow (VRF) HVAC systems present many advantages such as being energy saving and the capability of adjusting refrigerant mass flow rate according to the change of high rises occurrence. This paper deals with an experimental control volume exergy analysis in a VRF air conditioning system. The experimental results show that the brunt of the total exergy destroyed in the whole system occurs in the outdoor unit, where the exergy destroyed in the condenser is more important. The values of coefficient of performance (COP) obtained for the tests increase as the system reaches operational conditions imposed in every indoor unit zone. The VRF system analyzed is highly sensitive to the action of the constant speed compressor. The use of an inverter compressor improves the system performance by adjusting the power consumption according to the cooling load in the evaporators.

Excessive heat occurs during the semiconductor manufacturing process. Thus, precise control of temperature is required to maintain constant chamber temperature and also wafer temperature in the chamber. Compared to an industrial chiller, a semiconductor chiller's power consumption is very high due to its continuous operation for a year. Considering the high power consumption, it is necessary to develop an energy efficient chiller by optimizing operation control. Therefore, in this study, a semiconductor chiller is experimentally investigated to suggest an energy-saving direction by conducting load change, controlling the temperature's rise and fall and controlled precision experiments. The experimental study shows how the cooling capacity of new model chiller rises over 30% compared to the old model chiller. The time and power consumption in the temperature rising experiments are 43 min and 8.4 kWh, respectively. The control precision is the same as ± 1°C, at 0°C, in any case. However, it appears that the new model channel's control precision improves to ± 0.5°C when the setting temperature is over 30°C.

Experimental and theoretical studies were conducted to investigate the performance of a membrane-based energy recovery ventilator, which is an air-to-air heat exchanger with a water vapor permeable core. Tests were done on a commercially available membrane-based energy recovery ventilator, during which the supply and exhaust air states were recorded continuously over a long period of time. The test results show that as time passes the sensible effectiveness decreases very slightly from 56% to 55%, while the latent effectiveness increases appreciably from 28% to 39%. As a resultant of sensible and latent effectiveness, the enthalpy effectiveness provides an intermediate value between them and increases from 39% to 43%. The reason that the effectiveness changes with time is that the air relative humidity changes with time, which alters the moisture content at the membrane surface. Calculations were then implemented to predict the performance of the membrane-based energy recovery ventilator based on the model we developed previously and the calculation results were compared with the experimental data. The comparison suggests that the calculated effectiveness agrees well with the measured one, supporting the reasonability of the model. Calculations were also made to investigate the effects of various membrane parameters on latent and enthalpy effectiveness and latent-to-sensible heat ratio.

In this paper, the heat pump system has been developed by CFD simulation and experimental investigation. It studies the thermal behavior of a thermobank and COP on heat pump system and cold storage. The thermobank stores the waste heat of during refrigeration cycles and this energy is used for defrosting process and heating room. It also reduces defrosting time and condensation load so that the temperature regulation in the cold storage is constant. The system is investigated experimentally and CFD simulated under thermobank. The dimension $L\times W\times H$ of cold storage is $3\times 1.6\times 1.4$m, thermobank is $600\times 300\times 400$mm. The temperature of ambient on CFD simulation process is 20${}^{\circ }$C. This heat pump system can be used to keep preservation of agricultural products in cold storage warehouse together with floor panel heating for room in winter. The ejector is used in system with the aim of increasing coefficient of performance (COP) and decrease in compressor displacement. As the experimental results, its COP is increased about 38.57% when using thermobank and ejector in heat pump system.

When water chillers are arranged in series-series counterflow (SSCF), the compressor lift of each chiller is decreased in comparison with that of water chillers in parallel. This means that the compressor power of SSCF chillers is lower than that of parallel chillers. In this paper, models of the main components in an air conditioning system were developed and verified to predict the behaviors of the whole system with respect to SSCF chillers. The results showed that performance was maximized with three SSCF chillers when the system was operated with normal set points. The performance was further improved to 26% and decreased with the number of SSCF chillers when the system was operated with optimal set points. The SSCF chiller system also demonstrated higher exergy efficiency regardless of the number of SSCF chillers. The irreversibility of components in SSCF chillers was rather low. However, the irreversibility of the cooling tower and cooling coil was slightly higher and lower, respectively, than those in the parallel chiller system.

We studied the relevance of the secular variation of Japanese interest in energy and environmental problems to the information primarily released by the news media. From the investigation of the extent of public interest in three matters, the global warming, the energy saving and nature, all indicated by opinion surveys, the number of newspaper articles and the frequency of Internet retrieval search, we proposed a model such that the public interest along with the acquired public knowledge were given as a function of public memory of the information primarily provided by the news media. The society was assumed here to be immersed in a virtual field of information environment, which induced the collective interest of the public and was proportional in strength to the extent of the public memory with oblivion. Introducing two types of oblivion function, we found the model to well reproduce the real time-variation of the Japanese interest, except for the case of nature, almost irrespective to the form of the function. Some comments were made on the attenuation of the public interest that occurred when the field became weakened.

Utilizing multi energy sources synthetically and efficiently is one of the trends of energy systems in recent years. An air source heat pump heating system based on the photovoltaic power supply is proposed in this paper, and further research is done on it. As a high efficiency and energy saving environmental protection equipment, air source heat pump can not only alleviate the pressure of the energy demand, but also provide effective solutions for winter heating. We put forward theoretical model and practical model schemes for a certain office building’s air source heat pump heating system, and carried out the simulation of air source heat pump heating system based on photovoltaic power. Quantitative data of the whole heating season, such as the indoor air temperature, heat storage water tank’s water temperature, and the system power consumption, was obtained. Analysis results shows that the economic benefits of air source heat pump heating system is superior to the traditional central heating system.

Combined with cases of energy-saving existing building from home and abroad, this passage discusses about the reconstruction condition of existing buildings and makes a comparison by analyzing the existing buildings in terms of energy-saving technologies and relevant policies, which points out the existing energy-saving problems of existing buildings in Hot Summer and Warm Winter Zones in our country. Also, it sums up the experience of energy-saving reconstruction and finally proposes energy-saving measures.

It is a necessity to introduce sufficient fresh air intake to ensure adequate indoor air quality in a variable air volume (VAV) air conditioning system, however this comes at the cost of heavy wind load. This paper proposes the application of CO2 concentration control in the VAV control system as a measure of indoor air quality and to achieve energy saving operational control of the air conditioning system. The simulation results demonstrate that the proposed scheme is able to balance the energy consumption due to fresh air intake and indoor air quality. Therefore, the dual mode VAV system provides dynamic and steady-state performance, high precision control, and remarkable energy saving effects; and it has wide application prospects.

Bioinspired legged robots are a good option for field missions over complex terrain such as extraterrestrial landscape, disaster scenarios, etc. For these applications robots should exhibit good performance in terms of mobility, payload and endurance. In this work a control law to exploit the HADE leg dynamic features in order to save electrical energy by reducing the required mechanical work is presented. This control law is a force based impedance control scheme that considers the fact that the prototype is an underactuated mechanism. An analysis on the energy saving capabilities of the system, based on spring stiffness is theoretically performed and experimentally validated.