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This article presents the design of the air conditioning system in the building. In the project, ice storage for cold source and electric boiler thermal storage for heat source are taken while variable primary flow is used for water system. Taking into account the functions of each part, all air and fan coil unit with fresh air system are applied in ventilation system. The design of air exhaust system is introduced. A detail scheme about the annual operational regulation for energy saving is proposed. During the designing process, energy conservation is given enough attention, and the reliability of operation is also ensured.

To study practical methods about energy-saving and noise reduction of fan,by analysising energy consumption and noise formation mechanism of fan in evaporative condenser. on the basis of the fan structure optimization (large diameter fan equiped width blade, anteversion structure),adopting multi-blowers starting and stopping control independently and Variable frequency fan, Optimum solution of energy-saving and noise reduction of fan was obtained.

Solar absorption cooling systems are available from various reports, in large capacities up to several hundred kilowatts. However, in the range of small capacities ( 2 solar collector arrays, one absorption chiller with a rated cooling capacity of 8 kW, and a hot storage water storage tank of 3 m 3 in volume. The chilled water can be delivered either into fan coils or into radiant cooling panels, which are installed to satisfy the demands of the indoor thermal environment of the test room. As for the fan coil cooling mode, it was found that the average cooling output reached 4.27 kW during 9 h of operation under typical weather conditions for Shanghai. The PMV (predicted mean value, a measure of thermal comfort) inside the test room could be controlled between −0.29 and 0.32. With regard to the radiant cooling mode, an individual supply air unit was installed for the purpose of preventing condensation on the cooling panels. Comparing with the experimental results of the fan coil cooling mode, the average cooling output increased by 23.5%.

The objective of this work was to experimentally investigate the influence of air mixing fans on air temperature and humidity distribution in an arched roof greenhouse. The greenhouse was occupied by a tomato crop and equipped with two side roll-up openings for ventilation, a PVC pipe heating system and a fan coil heater. Furthermore, for air mixing purposes, an air mixing fan was used. Air temperature and relative humidity was simultaneously recorded in 17 positions equally distributed inside the greenhouse. Concerning the effects of air mixing fan on microclimate distribution, it was found that the mixing fan increased microclimate homogeneity. On the other hand, the use of fan-coil heater was found to increase microclimate heterogeneity. The maximum absolute air temperature and relative humidity difference (observed above the crop) between the centre of the greenhouse and the different measuring positions at the same level, was about 1°C and 4% respectively when the air mixing fan was not used and about 0.4°C and 1% respectively, when the air mixing fan was used. The use of a fan-coil heater increased the above mentioned differences to the level of about 1.7°C and 6% respectively when the air mixing fan was not used and about 1°C and 3% respectively, when the air mixing fan was used. Finally, it was observed that the use of an air mixing fan and/or a fan-coil heater reduced the greenhouse air relative humidity.

In view of the HVAC and fan-coil system utilizing geothermal water whose temperature range is from 60°C to 85°C,the objective function of system has been established. The temperature parameters of all levels and the optimum recharge temperature of geothermal water are obtained by using MATLAB software. At the end of the paper, supply-water temperature of load side influencing on the price and coefficient of performance of high temperature heat pump have been analyzed in theory.

Combined system of radiant cooling and dedicated outdoor air system (DOAS) has advantage in energy-saving and thermal comfort. In order to investigate the energy saving potential of the system under different climate conditions in China, Tianjin, Shanghai, Guangzhou, Chengdu and Xi’an were selected, where summer energy consumption of the combined system and fan coil + fresh air system in reference building was calculated with BIN method respectively. The results show that radiant cooling system has better performance in energy saving than fan coil system by saving of 12-16%. The system operation time and outdoor climate are main factors influencing energy saving effect.

The paper analyzes air conditioning systems of different coolants on the basis of an example of a typical office building. Depending on the type of a coolant fan coil unit, active chilled beams, variable refrigerant volumes and air cooling systems were designed. The article suggests hydraulic and aerodynamic calculations and evaluates initial investments, energy expenditures and operating costs of the compared systems. Considering economic calculations, the pay-back time of the systems was assessed and the sensitivity analysis of electricity prices was carried out. The results of the conducted investigation show the most appropriate analysed system for office buildings taking into account the efficient use of electricity and initial investments. Santrauka Tipinio administracinio pastato pavyzdžiu nagrinėjamos skirtingų šilumnešių vėsinimo sistemos. Atsižvelgiant į šilumnešio tipą suprojektuotos ventiliatorinių konvektorių, aktyviųjų šalčio sijų, freoninė ir orinė vėsinimo sistemos. Atlikti hidrauliniai ir aerodinaminiai skaičiavimai, įvertintos sistemų pradinės investicijos, apskaičiuotos energijos sąnaudos ir eksploatacijos išlaidos. Ekonominio skaičiavimo metu buvo įvertintas sistemų atsipirkimo laikas ir atlikta elektros kainų jautrumo analizė. Šio tyrimo rezultatai rodo, kokia sistema yra tinkama biurų pastatams pagal efektyvų elektros energijos naudojimą ir pradines investicijas. Raktiniai žodžiai: vėsinimas; šilumnešiai; ventiliatoriniai konvektoriai; orinė sistema; freoninė sistema; aktyviųjų šalčio sijų vėsinimo sistema

This paper presents on the development of an electronically controlled viscous cooling fan clutch actuator. Improvement in energy efficiency has been achieved by automation of the engine control system and enhancement of engine cooling systems. The engine cooling system uses On/Off viscous cooling fans that are applicable to wide range of engine loads with efficient energy consumptions. Depending on the temperature of the engine and the PWM signals, the power input and speed of the cooling fan automatically controlled by engine management system (EMS). Test results on the fan speed control according to the engine temperature are given in this paper.

A new adjustment law of supply water temperature of heat pump unit was presented by analyzing heat transfer performance and computing supply water temperature of fan coil unit (FCU) in this paper. The paper established the energy equations for air side, water side and FCU in dry and wet conditions, respectively. And the heat transfer performance of FCU was obtained by analyzing the manufacturers’ performance data. According to an actual central air-conditioning system of residential buildings, we calculated the daily inlet water temperature of FCU and proposed the adjustment law for supply water temperature. The results show that the supply water temperature of cooling design day is 9.3°C, the daily supply water temperature of cooling season is higher than 7°C; the supply water temperature of heating design day is 36.4°C, the highest in heating season is 38.5°C, which is below the rated supply water temperature of heat pump unit, 45°C.

Introduce the practicality of automatic angle modulation cooling fan used in the engine cooling, calculate the performance data when automatically adjusting angle fan in different installation angle during operation by Fluent, do a comparison analysis of the data, draw the curves of cooling fan flow-total pressure and flow-efficiency in the different installation angle, make sure the operation law of the fan and the range of adjusting angle, and proof the automatic angle modulation cooling fan meet the requirement of the engineering machinery engine cooling, adapt to the working conditions of engineering machine.

The temperature and humidity independent control (THIC) system, which controls indoor temperature and moisture separately, may be an attractive alternative to existing conventional HVAC systems for its prominent improvement on the overall system performance and utilization of low grade energy resources. In order to verify the effectiveness of THIC system, a pilot project has been implemented in an office building in Shenzhen, China. In the system, liquid desiccant fresh air handling units driven by heat pumps are utilized to remove the entire latent load of outdoor air supplied for the whole building, and chilled water at the temperature of 17.5 °C from chiller is pumped and distributed into dry fan coil units and radiant panels to control indoor temperature. This paper presents the results of field test of the system, which shows that the system can provide a comfortable indoor environment even in very hot and humid weather. The COP of the entire THIC system can reach 4.0. According to the energy usage data recorded from the year 2009, the energy consumption of the THIC system in the tested office building was 32.2 kWh/(m 2 yr), which demonstrates magnificent energy-saving potential compared with the conventional air-conditioning system (around 49 kWh/(m 2 yr)).

The paper analyzes the rotor imbalance of cooling fan for the engine, and come to influence coefficient per unit quality. We can easy count the practice balancer cooling fan rotor. This method is very simple.

This paper presents a design scheme of the stratified air conditioning system, in accordance with the temple hall’s large space and function characteristics. The indoor stratified air conditioning environment is formed by the low velocity air supply of fan coil units embedded below the Buddha statue. The interface of stratified air is only 1.7m high, because the large amount of air unavoidably penetrates the room due to the prohibition of closing the door. From the tested results, the design not only meet the temple hall’s operational requirements for decoration and the open front door, but also greatly reduces the energy consumption of the air conditioning at the cost of the comfortable feeling of air conditioning. In this work, some suggestions are also given in order to further improve the comfort and lower the energy use.

This study was carried out in order to reduce the amount of underground water which is used in the double layered single span plastic greenhouse for retaining heat. For this research, two plastic green houses of the double layered single span plastic greenhouse were installed. There was equipped of internal small tunnel for keeping warm air in the interior of the house. Then the internal small tunnel for keeping warm air was fitted with PVC duct of 50 cm in diameter filled with subsurface water. The surplus solar energy in the greenhouse was stored in the water in the PVC duct. Four FCUs (Fan Coil Unit), which has the capacity of 8,000 kcal per hour, were installed in the middle of the house, and a circulation motor in heat storage water tank was operated from 10:30 a.m. to 16:00 p.m. in order to circulate water between the water tank and the FCUs. Consequently about 5 degrees celsius could be maintained in the interior of the internal small tunnel for keeping warm air with the external temperature of lower than minus 5 degrees celsius. It appeared that the alteration of an internal temperature of the house was flexible depending on the sunlight during daytime. To prevent the water freezing, mixing antifreezing liquid in the water or operating FCU continuously was needed. Also, in order to use the surplus solar thermal energy on plastic green house of water curtain system efficiently, storing the surplus heat during daytime simultaneously finding a method of using water curtain systematic underground water happened to be important. As a result of this research, when the house's interior temperature is below zero the operation of FCU appeared to be impossible. Considering the amount of water used in the house with water-curtain-heating system is 150～ 200 ton per day, using the system mentioned in this research showed that reducing the underground water more than 80% in order to maintain the internal temperature as the level of 5 degree celsius at the extreme temperature of minus 5 degrees celsius.

The performance of different HVAC systems varies when coupled with different buildings. This paper examines the relationship between building heating and cooling load and subsequent energy consumption with different HVAC systems. Two common HVAC systems in use throughout the UK office building stock, variable air volume (VAV) system and fan coil (FC) with dedicated outside air system, have been coupled with a typical narrow plan office building with and without daylight control and for both cellular and open plan. The results presented in this paper clearly indicate that it is not possible to form a reliable judgment about building energy performance based only on building heating and cooling loads. For the two investigated systems, variable air volume system and fan coil with dedicated outside air system, the difference between system demand and building demand varied from over −40% to almost +30% for cooling and between −20% and +15% for heating. If a heat recovery unit is used, the difference in heating performance is even greater, rising to −70%.

Spread of household air conditioning system is continued to be increased. Along with the spread, the acknowledgement on product quality by the customer is increasing. Therefore, not only basic performances like cooling and power consumption but also design and noise level of in-house and external unit become the important factors. Axial fan in the external unit of air conditioning system is for ventilation and air supplying unit, and the related products have been widely adopted as household electronics, automobile engine, big sized blower in factory, tunnel, and subway. In this study, commercial 3-winged propeller fan from S company is modified to 2-winged fan for the cost reduction. Using 3D modelling, the fan shape is modified, and analysis flow is adopted to provide the way to reduce cost while maintaining the same wind capacity.

Hybrid Energy System (HES) is mainly based on proton exchange membrane fuel cell (PEMFC) technology, which is supplied by a fuel reforming process for hydrogen production, starting from natural gas. The exhaust heat from the PEMFC is evacuated to a thermal storage tank (TST) mixed with water provided by geothermal source, The bath (Hammam) Sidi Aissa 47 °C, TST hot water maintained to 47 °C is used in a fan coil for canteen heating in Si Ben Salah School located in Saida (NW of Algeria). Cooling is assured by the air conditioning sub-system made of a fan coil and heat pump using cool water tank. The experimental analysis of the air conditioning device is done for canteen application for cooling and heating modes. The feasibility study shows that using the geothermal sources located in Northern Algeria and low temperature PEMFC for air conditioning is a promising solution.

This paper presents a novel energy-efficiency control method for a fan-coil unit, the duty ratio fuzzy control method (DRFCM), which employs the concept of duty ratio on the electric valve control to fully utilize the cooling and dehumidifying capacity of a fan-coil unit when the control valve is closed. By means of mamdani-type fuzzy rules and functioning-fuzzy-subset inference methods, the duty ratio of valve and fan speed signals are decided according to the deviation and deviation changes of the room temperature. This paper adopts a two-water-pipe FCU system with a three-fan speed control and an electric water valve on-off control as test objects to verify the application effect of DRFCM. Program controllers and software tools are employed to conduct DRFCM. The conventional control method is applied by individual FCU controllers. Experimental results show that DRFCM could obtain at least 30% energy savings (not including chilled pump power savings) over the conventional control method. A preferable room temperature control effect could be achieved as well.

This study deals with exergetic assessment of an educational building heated by a conventional boiler in a heating center. The heating system is examined from the generation stage to the envelope of the building. In general the heat loss calculations are made using both energy and exergy analysis methods. The energy and exergy flows between the stages are obtained using a pre-design tool for an optimized building design. Energy and exergy losses are obtained to evaluate the performance of the system. A conventional boiler in the heating center and a fan coil unit in a room are considered in the analysis. Total exergy input rate is calculated to be 694.5 kW, while the largest exergy loss rate is obtained to be 333 kW. Exergetic efficiencies of the conventional boiler and the fan coil unit are also found to be 13.4% and 37.6%, respectively.

This study has investigated numerically and experimentally the flow characteristic of air-cooling fan for transmission oil cooler in the large-size diesel engine. Impellers of cooler were composed of eight normal-scale and eight small-scale blades in the zig-zag pattern. In order to increase the discharge pressure of cooling fan, turbo type of fan blade is proposed in the impeller for transmission oil cooler. The fluidic performance of cooling fan has been estimated numerically by using the commercial code and experimentally carried out with reference on AMCA Standard 210-99. As a result, it is confirmed that the numerical result for performance curve is in good agreement with experimental data.

A solar-powered adsorption chiller with heat and mass recovery cycle was designed and constructed. It consists of a solar water heating unit, a silica gel-water adsorption chiller, a cooling tower and a fan coil unit. The adsorption chiller includes two identical adsorption units and a second stage evaporator with methanol working fluid. The effects of operation parameter on system performance were tested successfully. Test results indicated that the COP (coefficient of performance) and cooling power of the solar-powered adsorption chiller could be improved greatly by optimizing the key operation parameters, such as solar hot water temperature, heating/cooling time, mass recovery time, and chilled water temperature. Under the climatic conditions of daily solar radiation being about 16–21 MJ/m2, this solar-powered adsorption chiller can produce a cooling capacity about 66–90 W per m2 collector area, its daily solar cooling COP is about 0.1–0.13.

As the grain temperature in a grain depot increases in spring and summer, deterioration of stored grain by mildew and pests can become serious. To solve these problems, a temperature control technique for the storage bin using a heat exchanger, fan coil units (FCU) and the abundant groundwater resources in Hangjiahu Lake in southern China was studied. The results indicated that the head-space temperature (HST) of the treated bin was controlled effectively; the maximum HST was less than 26°C. The maximum grain temperature of the surface layer (GT-SL) of the grain mass was less than 25°C in the treated bin, the increasing rate of GT-SL was stabilized. The average grain temperature (AGT) in the whole grain mass was less than 18.3°C. In the control bin, maximum HST was about 36°C, maximum GT-SL reached 28.7°C peak temperature, meanwhile, the rate of temperature increase in grain layers was rapid, with the AGT of 21.0°C. Using heat exchanger technology for 11 wks, the electricity cost was 1.175 RMB/t of grain. Therefore, a quasi low temperature grain storage (QLTGS) has been achieved in the experimental bin with this new method in Zhengjiang Province, China. It will have an important significance for safe grain storage.

Higher room temperature can still let the occupants have a neutral thermal sensation if higher air speed is provided. With a suitable scheme of neutral temperature and comfort air speed, reduction of energy consumption of the central chiller plant may surpass the additional energy requirement of the air side equipment, then both energy saving and thermal comfort can be achieved for the entire air-conditioning system. To evaluate this, the energy consumptions of a centralized air-conditioning system using the common air side alternatives were studied for the subtropical Hong Kong. The alternatives are variable air volume (VAV) system, constant air volume (CAV) system and fan coil (FC) system. Each of them was associated to a central chiller plant to serve a high-rise office building. The studying range of the room air temperature was from 23 °C to 30 °C. It is found that the VAV and FC systems can provide both thermal comfort and energy saving for higher room temperature, but CAV system is not feasible when the room air temperature is above 27 °C. If the indoor air speed threshold is considered, the neutral temperature can be brought up to 26.5 °C, and the energy saving potentials of VAV and FC systems would be 12.9% and 9.3% respectively.

This paper is concerned with the experimental analysis of a standard terminal fan-coil unit with ice slurry as coolant. The ice slurry was produced from an ethylene glycol 10 wt% aqueous solution. The pressure drop measurements are presented as a function of volumetric flow rate, ice concentration and Reynolds number. The experimental friction factors are obtained and discussed. The fan-coil capacity was experimentally determined for chilled water and melting ice slurry with inlet ice fractions around 5, 10, 15 and 20 wt%, considering in each case three different fan rotation velocities. The fan-coil capacity is higher with melting ice slurry than with chilled water by factors between 3.7 and 4.9. The heat transfer analysis realizes that the air side thermal resistance controls the heat transfer process. Experimental results for the melt off rate of ice in the fan coil and the superheating at the fan-coil outlet are shown and discussed.

A discrete model characterizing heat and fluid flow in connection with thermal fluxes in a building is described and tested against experiment in this contribution. The model, based on a cellular automaton approach, relies on a set of a few quite simple rules and parameters in order to simulate the dynamic evolution of temperatures and energy flows in any water or brine based thermal energy distribution network in a building or system. Using an easy-to-record input, such as the instantaneous electrical power demand of the heating or cooling system, our model predicts time varying temperatures in characteristic spots and the related enthalpy flows whose simulation usually requires heavy computational tools and detailed knowledge of the network elements. As a particular example, we have applied our model to simulate an existing fan coil based hydronic heating system driven by a geothermal heat pump. When compared to the experimental temperature and thermal energy records, the outcome of the model coincides.

At the University of Szeged Faculty of Engineering we design solar collectors since 2005. For the tests of our collectors and for other researches about collectors we designed a measuring equipment which is capable for measuring the efficiency as the function of the specific solar irradiation and the temperature difference between the collector and the ambient air. The temperature different between the collector and the ambient air in our system is well-controlled with the fan coil which transfers the heat from the collectors to the ambient air. With this construction we can change the temperature of the fluid at the intake of the collectors and simulating transient effects. By the data loggers we have registered the values every 5 seconds. The calculation of the instantaneous efficiency of solar collector is conditioned. Based on the results of the measurements the MATLAB model of the analysed solar collectors is developed. During the design of a flat solar collector with this model the function of the efficiency could be pre-calculated.

This article experimentally and numerically investigates the thermal performance of a large-scale motor with a capacity of 2350 kW. The large-scale motor consists of a centrifugal fan, two axial fans, a shaft, a stator, a rotor and a heat exchanger with 637 cooling tubes. The test rigs are set up to measure the performance of the fans and the temperature distributions of the motor. The models of the fan and motor have been implemented in a Fluent software package to predict the flow and temperature fields inside the motor. The calculated results show good agreement with the measured data. In order to improve the motor thermal performance, several methods have been adopted, which are aiming to enhance the fan performance by changing the geometry, to redesign a new heat exchanger with guide vanes, and to optimize the distance between the axial fans. The modified design can decrease the temperature rise by 6 °C in both the stator and rotor.

The effect of the pitch of the blades in an axial fan with an UK-2M impeller 2.8 m in diameter on the characteristics of a horizontal three-section air cooler (AC), the six-tier heat-exchange sections of which consist of bimetallic finned tubes with rolled aluminum fins (tube-finning factor of 20.4; medium cooled – gasoline) is analytically investigated. It is found that for the same power consumed by the fan drive, the pitch of the fan blades in the interval from 15 to 25° will not affect the thermal flux of the AC. Recommendations are given for selection of energy-expedient pitches of the blades during AC operation, and also for thermal analyses of units under design.

An experimental investigation on operation characteristics of cool storage air-conditioning system with spherical capsules packed bed was performed in this paper. The experimental system of cool storage air-conditioning system with spherical capsules packed bed was set up. The performance parameters such as the evaporation pressure and the condensation pressure of refrigeration system, the refrigeration capacity and the coefficient of performance (COP) of the system, the cool storage rate and the cool storage capacity in the cool storage tank, the inlet and outlet coolant temperatures in the cool storage tank during charging period, and the cool discharge rate and the cool discharge capacity in the cool storage tank, the outlet and inlet coolant temperatures in the cool storage tank and the outlet and inlet air temperatures in room fan coil unit during discharging period were investigated. The experimental results indicated that the cool storage air-conditioning system with spherical capsules packed bed has better performances and can stably work during charging and discharging period.

In this work, the combined effect of the energy conservative variable refrigerant volume (VRV) system and the variable air volume (VAV) system was experimentally investigated using genetic fuzzy optimization method that yielded better thermal comfort, indoor air quality (IAQ) requirements without compromising on the energy savings potential. The proposed system was tested using the demand controlled ventilation (DCV) combined with the economizer cycle ventilation (ECV) techniques and examined for a year-round building air conditioning (A/C) application. The supply air temperature (SAT) set points were varied under three distinct strategies and the optimal solutions obtained for the fuzzy systems designed resulted in an enhanced energy conservative potential. The test results of the proposed system were compared with the conventional fan coil A/C system. Based on the three strategies of the supply air temperature, the proposed system yielded an improved per day energy savings potential of 54% in summer and 61% in winter design conditions. Furthermore, for the strategies considered the proposed system achieved an annual energy conservative potential of 36% and exhibited more possible ways to achieve thermal comfort, IAQ and energy conservation.

In this paper, an economic analysis of systems adopted as the perimeter zone system in office buildings such as convector, fan coil unit(FCU) and fan powered unit(FPU) was performed, with the variable air volume(VAV) system applied in the interior zone. The initial cost of each alternative, such as the construction cost of the air conditioning system, was determined by planning and design, and energy cost as running cost was calculated on the basis of the energy consumption of each system using a computer simulation. Economic analysis was performed using life cycle cost(LCC), with the present value method for the air conditioning system in the perimeter zone. The results show that FPU is the most economical air conditioning system. When VAV is applied to the interior zone, LCC of the FCU is reduced by 6% and the cost of FPU is reduced 9% less than that of the convector system.

A domestic-scale prototype experimental solar cooling system has been developed based on a LiBr/H2O absorption system and tested during the 2007 summer and autumn months in Cardiff University, UK. The system consisted of a 12 m2 vacuum tube solar collector, a 4.5 kW LiBr/H2O absorption chiller, a 1000 l cold storage tank and a 6 kW fan coil. The system performance, as well as the performances of the individual components in the system, were evaluated based on the physical measurements of the daily solar radiation, ambient temperature, inlet and outlet fluid temperatures, mass flow rates and electrical consumption by component. The average coefficient of thermal performance (COP) of the system was 0.58, based on the thermal cooling power output per unit of available thermal solar energy from the 12 m2 Thermomax DF100 vacuum tube collector on a hot sunny day with average peak insolation of 800 W/m2 (between 11 and 13.30 h) and ambient temperature of 24 °C. The system produced an electrical COP of 3.6. Experimental results prove the feasibility of the new concept of cold store at this scale, with chilled water temperatures as low as 7.4 °C, demonstrating its potential use in cooling domestic scale buildings.

For heating, ventilating, and air-conditioning (HVAC) systems for commercial buildings, the cooling coils in air-handling units (AHUs) account for a significant fraction of total building energy consumption and have a major impact on comfort conditions and maintenance costs. Development of cost-effective advanced control strategies will enhance the performance and efficiency of AHUs. The control design process can be greatly facilitated with simulation on a high-fidelity dynamic model prior to experimental validation and implementation. This paper presents a dynamic model for a chilled-water cooling coil. The model development was based on Dymola and Air Conditioning Library with some revision on heat exchanger modeling. For chilled-water cooling coil modeling, the major challenges include the variation of coil surface conditions under flow rate changes and partially-dry-partially-wet operations. This study proposes a dynamic coil model that is capable of predicting cooling performances under fully dry, p...

The drive force of engine cooling fan increases in the proportion of engine size and operation velocity. It's one of the reasons of engine power consumption and is the main source of engine noise and vibration. Generally, insufficient fan revolution results in overheating and poor cooling operation. In case of engine overcooling the driving horse power decreases and results in engine noise. If a fan is kept in operation continuously, poor fuel economy, unwanted noise and battery dead will be caused. In case of cooling fan by thermostatic coil spring, even the advantages of viscous cooling fan clutch, it's impossible to control precise engine temperature and fan revolution velocity because of its only On/Off function for valve lever by bimetallic spring with two different thermal coefficients. Hence, it's imperative to apply high edge electronic systems to solve strict technology issues and it's essential to apply electronic sensor and actuator for vehicles which requires high environmental protection and reliability in harsh service areas. In this paper, the optimization of engine management system (EMS) controlled viscous cooling fan was investigated to control cooling fan drive and its velocity by direct engine temperature and engine management system according to PWM signals.

This study focuses on the effect of outdoor coil fan speed on the performance variation of the heat pump system by adopting the hot gas bypass method, and on the performance improvement with hot gas bypassing using the time step method to defrost. Tests were conducted for fan speeds 90, 60 and 30% of the normal speed of the outdoor coil together with the stationary case. Performance of the heat pump is compared with the conventional time step defrosting method for coefficient of performance (COP) and total heat capacity. Results show that the integrated heating capacity with hot gas bypassing is highest at 60% (780 rpm) of the fan speed and is 8.6% higher than that of the time step defrosting method. The averaged COP of the heat pump in this case is higher by 3.8% than the time step defrosting method and 2.8% higher than that of the stationary fan.

The application of heat and enthalpy wheels in HVAC systems has been steadily increasing, powered by the cost reduction associated with the decrease of the thermal load they provide. Heat wheels are usually employed to pre-cool the fresh air stream before it is admitted to the fan coil. When impregnated with a hygroscopic material, heat wheels are often referred to as enthalpy wheels, and are also capable of drying the make-up air supply, thus providing a further thermal load reduction. Accordingly, the present work aims at developing a simple mathematical model to describe the heat and mass transfers in rotary exchangers, which is validated by comparing the present with independently obtained results. An Effectiveness-number of thermal units (NTU) analysis is carried out, the results showing that heat wheels can be far less efficient than enthalpy recovery wheels, depending on the atmospheric conditions.

An all-air central air-conditioning system with an exhaust fan incorporated with a supply fan is presented in this article. With the proposed system, detailed year-round energy-efficient operation strategies and control methods for the air-handling unit are presented. Further, the method of determining the pressure head and air volume of the exhaust fan is also presented, which is needed for designing this presented system. As opposed to conventional one supply-fan systems in the all-air central air-conditioning system, the proposed system is shown to not only maintain indoor pressurization required for controlling indoor air quality but also operate in an improved energy-efficient manner, achieved by having proper variable fresh-air ratios during the period of intermediate season. Due to its increased outdoor air, the proposed system can improve indoor air quality further.

A commercial fan coil has been experimentally studied in this work in order to assess its behaviour when ice slurry is used as secondary refrigerant. Experimentally obtained results have been compared to theoretical prediction obtained using the correlations proposed in previous papers in order to verify them. Several reasons have been reported to explain the deviation of fan coil behaviour from that expected and which make the direct application of ice slurry inappropriate in the fan coil studied. In order to avoid those problems and to establish a comparison between two secondary refrigerants with similar cold storage capacity, ice slurry direct application has been compared to ice slurry indirect application – only carrier fluid, without ice particles, flowing through the fan coil. The most remarkable conclusion obtained is that indirect application improves the behaviour of the fan coil studied for all the cases analysed, overcoming the problems reported for direct application.

In a warm environment air movement with elevated velocity is a well-known cooling strategy. The local air movement is typically generated by cooling fans (e.g. ceiling fan, table fans, etc.). Appearance, power input and price are the main parameters considered today when purchasing cooling fans, while their cooling capacity and efficiency of energy use are unknown. A new index is introduced, named “cooling fan efficiency index” defined as the ratio between the cooling effect (measured with a thermal manikin) generated by the device and its power consumption. The index was determined for a ceiling fan, a desk fan, a standing fan and a tower fan in a real office at three room air temperatures and at different fan speed levels. The results revealed that the index is sensitive enough to identify differences in the performance of the cooling devices. A standard method(s) for testing fan cooling effect and index(s) for determination of their efficiency, such as the proposed in this study cooling fan efficiency index, need to be developed. The cooling fans generate a non-uniform velocity field around occupants which cannot be described with a single air velocity value. Therefore it is not clear how to apply in practice the recommended in the present standards eleveted velocity in a warm environment. The standards need to be revised.

Continuous commissioning (CC) utilizes the HVAC system retrofit with system optimization theory and advanced technologies in a federal outpatient clinic building. The case study building has a basement and a first floor with patient rooms, offices, and a pharmacy. The HVAC system consists of two single-duct VAV air handling units (AHUs), 112 single-duct pneumatic controlled pressure independent terminal boxes, and associated hot/chilled water booster pumps. Both AHUs share one heat recovery heat exchanger. Major retrofit efforts include installing a VFD on the exhaust fan and reheat hot water pump, and installing fan airflow stations (FAS) and pump waterflow stations (PWS). This article presents optimal control strategies, which include outside air intake control, heat recovery from exhaust air control, supply fan control integrated with FAS, return fan control, optimal control for terminal boxes, and hot water and chilled water pump speed control. The measured daily utility data after CC shows t...

Generally, automobile cooling fan is used to lower the temperature of radiator. The cooling fans are manufactured by plastic injection molding process. The center of gravity of cooling fan is often deviated from the center due to the use of deteriorated materials. As the unbalanced of the cooing fan can generate noise, it is required to measure the degree of deviation of center of gravity in the cooling fan. In this work, automatic fan balancer which can effectively detect the magnitude and position of the unbalanced cooling fan is proposed and several experiments are carried out to verify the feasibility of the proposed algorithm.

Real-time control of air conditioning needs dynamic models of temperature distribution and air velocity field in rooms. Complete models, based on computational fluid dynamics (CFD), give this information, but they are too time-consuming for real-time applications. Therefore, a reduced model is needed. In mixed convection, when the air temperature has negligible variations, the velocity field may be considered fixed. In this case, the size of a CFD model may be reduced by solving only the energy balance equation, then putting this equation in the form of state-space and finally by reducing its order by proper orthogonal decomposition (POD). This algorithm was applied to a room equipped with a fan coil. Four fixed airflow fields, corresponding to negligible air temperature variation, were considered, resulting in four airflow patterns: the air jet sticks to the ceiling and reaches the opposite wall, the air jet falls before reaching the opposite wall, the air jet reaches the ceiling without extending along it, and the air jet falls before reaching the ceiling. The reduced model obtained from these airflow patterns was validated by comparing with CFD results for step variation of inlet temperature. As the order of the reduced model is always lower than seven, it may be used for real-time control applications.

This paper presents the study of the novel thermoelectric heat pipe heat pumping system. Bent heat pipes with sintered powder wicks were utilized in a configuration which used centrifugal forces, due to rotation, to enhance heat transfer. The revolving heat pipes worked both as a fan and as a heat exchanger; however, extra fan blades were required to improve the fan performance. Fan performance tests were carried out, followed by the thermal performance, within which eight pieces of thermoelectric devices were applied to provide the heat pumping. The results showed that the system could provide airflows of up to 168.7 m-super-3/h with the revolving speed of 600 RPM, and maximum static pressure was up to 37 Pa. The system could supply the heating of up to 257.1 W with the coefficient of performance of up to 1.96. Comparisons were made between the revolving and stationary systems, and the results showed that the former increased the thermal performance by up to 10% in heating and up to 20% in cooling. Copyright The Author 2009. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org, Oxford University Press.

Traditional design methods to achieve improvement in heat sink performance are not suitable for meeting new thermal challenges. Revolutionary rather than evolutionary concepts are required for removing heat from the electronic components. We have recently developed an emerging novel approach, the integration design of the forced convection air cooling system. The aerodynamic design for the miniature axial-flow fan is conducted and a CPU fan is designed to be integrated with the radial fins in order to form a complete fan-heat sink assembly. The 3-D data of the fan generated by FORTRAN program are imported into Pro/E to create its 3-D model. The performance curve of the fan prototype fabricated by the computer numerically controlled machine is tested in a standard wind tunnel. To reduce the economic cost and prompt the design efficiency, the computational fluid dynamics is adopted to estimate the initial fan's performance. A series of radial heat sinks is designed in accordance with the outflow angle of airflow discharged from the fan. The inlet angle of the fin is arranged so that the incoming flow from the upstream impeller matches the fin's angle of heat sinks. Using the multi-block hexahedral grid technique, the numerical simulation of the system, including the fan and heat sinks, is performed by means of Multiple Reference Frame (MRF) and RNG k-epsiv Model. Our results indicate that the thermal resistance of the streamlined heat sink is decreased by 15.9% compared to the traditional heat sink and the entropy generation rate of the streamlined heat sink is lower. The experiments support our simulation results. The series of heat sinks is able to achieve the productive thermal performance when the integration design concept is utilized.

： The miniaturization of the Air Handling Unit (AHU) has become an actual need because of the restriction of the using space on the vessel. In modern AHU’s construction, in which the fan section is at the end part of the ship, it’s very difficult to select a suitable capacity of evaporators, because the fan motor emits heat. Thus, the AHU structure has been changed as the fan section has been set before the cooling coil to get temperature values similar to the designed amount. Also, the air guider is installed in order to maintain equal air distribution after it passed the fan section. So, it is possible for air to equally pass the cooling coil. It is investigated three different geometries to find the best performance. Also, It is compared with the numerical and experimental results. The study found the case 3 gives the best results. The results of this study show the possible application of the new design. Key words ：AHU(공조장치), Air guide(공기 가이드), Cooling coil(냉각코일) †교신저자(부경대학교 공과대학 기계공학부 , E-mail : ekim@pknu.ac.kr, Tel : 051-629-6182)* 부경대학교 냉동공조공학과

본 연구에서는 냉방운전 시에 팬코일 유닛에 사용되는 핀-관 열교환기의 공기측 열전달 능력과 압력강하를 실험을 통하여 조사하였다. 실험을 위하여 칼로리미터와 항온수조를 이용하였다. 사용된 핀은 슬릿핀이며 5종 열교환기에 대해 배관회로와 실험조건을 변화하면서 실험하였다. 공기-물 정격유량에서의 냉방능력은 열교환기 공급 물온도가 낮은 조건이 우수하였으며, 배관회로에 따른 냉방능력은 배관 내 물흐름이 U형보다 ㄹ형인 경우에 더 크게 나타났다. 물유량이 증가할수록 냉방능력은 일정비율로 증가하였으며, 열교환기 공급 물 온도가 낮을 때 우수하였다. 공급 물 온도가 낮은 조건에서 많은 응축수가 생성되어 공기측 압력강하는 크게 나타났다. 【An experimental study has been performed to investigate the air-side capacity and pressure drop of the fin-tube heat exchanger for a fan coil unit under a cooling condition. The experimental data of five kinds of slit fin-tube heat exchangers were measured using an air-enthalpy calorimeter and a constant temperature water bath. Cooling capacities at the air and water rating flow rates were larger at the lower inlet water temperature. With increasing the water flow rate, the cooling capacity increased at the constant rate. Under the lower inlet water temperature, since the condensate was generated more on the fin-tube surface, the air-side pressure drop of the heat exchanger was larger.】

This chapter covers ways of conditioning the air to be delivered and circulated to the rooms or equipment that needs to be cooled. Air can be cooled and treated for humidity by air handling units, integral units or split systems. Large air handling systems tend to be cumbersome and so water is frequently used to transport the cooling to where it is required. Advantages and disadvantages of these approaches are given. Transfer from water to the air is made by localised fan-coil units or static cooling devices. The proportions of fresh air and recirculated air must be considered. The alternative is to place the refrigerant evaporator directly in the cooled room and circulate refrigerant from a central condensing unit. In its simplest form it is a split system with one evaporator, and a multi-split when several evaporators are employed. This leads to the more complex VRF systems covered in chapter: Heat Pumps and Integrated Systems. Brief reference to transport systems is given and two specialist applications are dealt with in more detail. These are data cooling centres and de-humidifiers.