1、VOLUME 14, NUMBER 4 HVAC costbenefits, scalability of the network; simpler and more flexible system design; faster and less dis-ruptive installations and retrofits; and smoother and less costly migrations staged to accommo-date budgets and schedules.Flexibility is the ultimate benefit in deploying a
2、 wireless system compared to a wired net-work. Sensors can be located, or relocated, to optimize system performance; increase cus-tomer comfort; and adapt to changing floor plans. Many wireless technologies and productsare available in the current BAS industry, and a number of companies are paid to
3、developwireless technologies for BAS applications. It is likely that wireless BASs will be popular inBAS installations in the very near future; however, many aspects regarding the technologystill need to be addressed.CURRENT WIRELESS TECHNOLOGIES ASSOCIATED TO BASSThere are many short-range wireless
4、 communications technologies available now in informa-tion technologies, automation, and other mobile data communication fields. The wireless tech-nologies related to the BAS applications include ZigBee technologies, 802.11 compliant(WiFi) technologies, Bluetooth technologies, and other proprietary
5、technologies.ZigBee TechnologiesThe ZigBee Alliance developed a network specification that is built upon the IEEE 802.15.4radio. The standard was approved in December 2004 and adds logical network, security, andapplication software. The standard was created to address the market need for a cost-effe
6、ctive,standards-based, wireless networking solution that supports low-power consumption, low datarates, security, and reliability (Raimo 2007). Potential applications include home automation,building automation, and automated meter reading, as well as industrial monitoring and control.The range of t
7、he ZigBee device is about 100 to 300 ft for typical buildings, which makes itwell-suited for building automation applications. ZigBee defines multiple network topologies, or configurationsstar, mesh, or cluster tree,which is a combination of the star and mesh topologies. The most suitable topology v
8、aries byShengwei Wang is a professor in the Department of Building Services Engineering, The Hong Kong PolytechnicUniversity, Hong Kong.2008, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in HVAC accepted March 26, 2008An analysis of the
9、ventilation effectiveness of a prototype personalized ventilation system ofworking places named PERMICS-LOS1 (Personal Microclimate System) was made, based onmeasurements of the air velocity field and of tracer gas concentrations using the decay method.The emphasis of the analysis was mainly on an e
10、xperimental verification of a parameter basedon the relative decrease of tracer gas concentration in the first minute of system operation dC(1)and on local ventilation efficiency using the local air-change index L. A system analysis wasmade for several different operating regimes of personalized ven
11、tilation, where changes in airquantity and the direction of supplied air in the breathing zone were applied. The results of theexperimental analysis were statistically evaluated, compared, and included in the existing data-base of previous research for use as supplementary values. The performed anal
12、ysis has con-firmed previous findings as well as the connection between the dC(1) parameter and ventilationeffectiveness parameters, especially with the local air-change index.INTRODUCTIONIndoor air quality and the importance of providing a healthy and comfortable indoor environ-ment for occupants h
13、ave been drawing more and more attention (Butala et al. 2001a). Mostareas within buildings space in which fresh air is normally supplied by mixing ventilation or dis-placement ventilation systems can be polluted by various indoor air contaminants before the airis inhaled by the occupants. People hav
14、e also become more aware of sick building syndrome(SBS) (USEPA 1991) and building-related health complaints, which represent significant healthproblems, such as headaches, allergies, and fatigue. The main cause of SBS is a poorly ventilated working area (WHO 1984), which depends onseveral influencin
15、g parameters, such as the type of ventilation and HVAC system, the hygienicquality of the inlet air, and classical physical factors in the environment. The parameters interactto influence peoples health conditions and feeling. SBS has a significant economic impact thatis manifested in decreased prod
16、uctivity and absence from work, as well as the consequentlyhigher health care costs of employees (USEPA 1989; Wargocki et al. 1999, 2000). On this basis, a new approach based on the philosophy of excellence for future air-conditionedenvironments was proposed by Fanger (2001). He suggested narrowing
17、the air-conditioned spacefrom the whole room space to the local space within the occupants breathing zone, and proposed anovel personalized air (PA) system that would gently serve a small amount of cool, clean air closeto or directly into the breathing zone of each individual without causing a draft
18、.Simon Muhi is an HVAC specialist at Sineco, Ljubljana, Slovenia. Mitja Mazej is a researcher and Vincenc Butala isan associate professor in the Faculty of Mechanical Engineering, University of Ljubljana, Slovenia.2008, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.
19、(www.ashrae.org). Published in HVAC Muhi and Butala2002, 2004; Butala and Novak 1997), conclusions similar to Fangers proposal were presented(Muhi and Butala 2006). There is a need for more qualitative ventilation or air-conditioningsystems for workplaces. New systems with a personalized inlet of fr
20、esh air will allow local reg-ulation of key indoor environment parameters. This concept of a properly designed personalizedventilation system makes it possible to achieve high local ventilation efficiency with a verysmall fresh airflow rate and satisfactory thermal comfort parameters for each occupa
21、nt. Researchers of the personalized ventilation applications evaluated performances of differentair terminal devices under many operating regimes in terms of flow rate, temperature of person-alized air, and space air temperature, using an index named the “personal exposure effective-ness” (Melikov e
22、t al. 2002; Naiping and Kianlei 2004; Niu et al. 2007; Sekhar et al. 2005).Proper design and orientation of an air terminal device and the temperature of personalized airhave a great impact on achieving very high rates of personal air in inhaled air (Bolashikov et al.2003), and the most critical fac
23、tor in improving the efficiency of personal air distribution is thelocation of an air terminal device (Kaczmarczyk et al. 2006; Jeong 2003; Faulkner et al. 2004).However, it was also found that in some special cases personalized ventilation did not ensurebetter inhaled air quality due to the influen
24、ce of the location of pollutant sources and the back-ground air-conditioning system (Cermak and Melikov 2003; Melikov et al. 2003). The resultsshowed that personalized ventilation will always be able to improve the inhaled air quality inspaces with a mixing ventilation concept, but that the improvem
25、ent in rooms with displacementventilation still depends on the ventilation efficiency of the personalized ventilation system andits ability to promote mixing. In such cases, personalized ventilation can strengthen the contam-inant transport in the breathing zone so that there is a higher risk of per
26、sonal exposure observed(Cermak et al. 2006). This is the reason why ventilation efficiency of the personalized ventila-tion system is an important and influential parameter that must be measured and calculated forthe assessment of system operation.In our previous studies of personalized ventilation
27、effectiveness, a new index of relativedecrease of tracer gas concentration in the first minute of system operation dC(1) was defined(Muhi and Butala 2006; Muhi 2004). The parameter dC(1) can be used for direct measure-ment of ventilation efficiency in a shorter time. On the basis of dC(1) measuremen
28、ts, the compu-tational fluid dynamics (CFD) simulations using the same boundary conditions were carried out,which have successfully verified the results of dC(1) measurements. This set the groundwork forthe design of a new system for personalized ventilation, PERMICS-LOS1. PERSONALIZED VENTILATION S
29、YSTEMPERMICS-LOS1Personalized ventilation systems are designed for implementation in places where occupantsare sitting in the same place for longer periods of time. An important factor in the concept of apersonalized ventilation system is the application strategy used in terms of conditioning-spacea
30、ir and personalized air. The accepted strategy is the maintenance of space air in the same wayas in conventional air-conditioning systems and to use personalized air only to fulfill the indi-vidual preferences. A newly developed and tested personalized ventilation system of working area, PER-MICS-LO
31、S1, is mainly based on PERMICS (Muhi and Butala 2006; Muhi 2004), as well as onother personalized air systems (Melikov et al. 2002; Naiping and Kianlei 2004; Niu et al. 2007;Sekhar et al. 2005; Bolashikov et al. 2003; Kaczmarczyk et al. 2006; Jeong 2003; Faulkner et al.2004; Cermak and Melikov 2003;
32、 Melikov et al. 2003; Cermak et al. 2006). A novel system wasdesigned as an individual unit for local air distribution directly into the breathing zone of the occu-pant, sitting at an office desk in an office with several employees. This makes it possible to custom-ize the working area environment t
33、o the preferences of each individual by allowing adjustments of2008, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in HVAC Sandbergand Sjoberg 1982; Mundt et al. 2004). CO2concentration was measured using a system for CO2measurements with
34、 infrared absorption sensors at four locations, namely in fresh supply air, atthe air terminal device, at the manikin head, and at the outlet from the test chamber. The CO22008, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in HVAC howeve
35、r, the second curve (EPS_L-new) takes into account all mea-surements taken on both systems. An evaluation of the expanded database with additional parame-ters for seven measurements shows that there is still a strong correlation between dC(1) andTable 1. Measured and Computed Parameters for Differen
36、t Operating ConditionsMeasurement M1 M2 M3 M4 M5 M6 M7Q, L/s 3.50 2.53 2.58 3.50 3.53 2.54 3.50, 30 30 30 30 15 15 15Mesh screen no no yes yes yes yes yesvnose, m/s 0.25 0.17 0.12 0.19 0.04 0.01 0.04Tunose, % 13.78 16.91 19.01 20.39 54.32 83.62 50.97v200, m/s / / 0.07 0.08 0.31 0.20 0.25Tu200, % / /
37、 35.16 36.31 10.45 13.17 11.01dC(1) 0.348 0.343 0.381 0.401 0.359 0.330 0.258C(0), ppm 2579 2522 2423 2671 2542 2250 2229C(1), ppm 898 866 922 1070 913 742 576Tin, C 24.5 25.1 24.5 25.0 24.8 24.4 24.9L, min 118.1 141.0 130.4 111.2 142.8 159.2 156.2n, min 253.3 350.2 344.3 253.7 251.2 349.9 253.8L, %
38、 214.43 248.37 263.99 228.14 175.88 219.73 162.452008, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in HVAC accepted March 26, 2008In order to develop a computational thermal manikin to enable the prediction of the thermalsensation of an
39、 occupant in a non-uniform environment, in a previous paper (Zhu et al. 2007)we proposed and examined a simulation method combining Smiths human thermalphysiological model with convective and radiant simulation by applying the proposed method tocalculate the sensible heat transfer over the body surf
40、ace of an occupant located in severalradiant environments with an air temperature of 28C. However, the simulation results greatlyunderestimated the skin temperatures at the limbs, even in uniform conditions, due to theimproper modeling of the Arteriovenous Anastomose phenomenon in Smiths model. Acco
41、rd-ingly, a new human thermal physiological model, Sakois model (Sakoi et al. 2005a, 2006a),was developed with a three-dimensional body configuration similar to Smiths model and athermo-regulatory mechanism by Yokoyama (1993). In this paper, Sakois model is coupled inthe simulation of convection, ra
42、diation, and moisture transport to calculate the total (sensibleand latent) heat transfer from a seated human body in uniform and front-back asymmetricradiant environments, which were introduced in the previous paper (Zhu et al. 2007). Thecomparison to the corresponding results of the subject experi
43、ments and the coupled simulationusing Smiths model in terms of skin temperatures indicates that the prediction accuracy of thenumerical simulation is greatly improved as a whole, especially at the limbs; however, it deteri-orates around the face and body parts facing cold panels when using Sakois mo
44、del.INTRODUCTIONOne of the most important research targets in the field of heating, ventilating, and air condi-tioning (HVAC) is thermal sensation. In 1997, Murakami et al. proposed a numerical analyticaltooldefined as a computational thermal manikin on the basis of coupled simulation of compu-tatio
45、nal fluid dynamics (CFD), radiation, moisture transport, and heat transfer inside the humanbodyas a new resolution method with regard to thermal sensation. Since then, it has beenShengwei Zhu is a postdoctoral research fellow at the International Centre for Indoor Environment and Energy, Depart-ment
46、 of Civil Engineering, Technical University of Denmark, Lyngby, Denmark. Shinsuke Kato is a professor andRyozo Ooka is an associate professor at the Institute of Industrial Science, The University of Tokyo, Tokyo, Japan.Tomonori Sakoi is a researcher and Kazuyo Tsuzuki is a group leader at the Natio
47、nal Institute of Advanced IndustrialScience and Technology, Tsukuba, Japan.2008, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in HVAC in addition, a human bodywith a complex shape that included feet, arms, jaw, and breasts was used in th
48、e CFD and radiantsimulations. The coupled simulation method was applied to calculate the heat transfer over thebody surface of a person in uniform and front-back asymmetric radiant environments. Accordingto the results, although the simulation results closely reflected the effect of the warm/coldrad
49、iation on the local heat transfer, the local skin temperatures differed greatly from thoseobtained in the corresponding subject experiments at the limbs, even in a uniform environment. Itcan be concluded that the improper modeling of the Arteriovenous Anastomose (AVA) phenom-enon in Smiths model is primarily responsible for the large discrepancy generated at the limbs.In view of the above results, a new human thermal physiological model, Sakois model, wasdeveloped with a 3D body configuration similar to Smiths model (Sakoi et al. 2005a, 2006a). InSako
