1、 -c - C. Circle No 1 on Reader Service Card or visit www pub-SeN comlrslashrae 3 G reenhecks model ERT with the NeutralizerTM coil section is the most efficient product available for con- ditioning humid outdoor air into “space neutral” air. And its economical design will fit your budget. This uniqu
2、e solution combines enthalpy wheel and heat pipe technologies. The wheel recovers energy from the exhaust air, cooling and dehumidifying the outdoor air. The heat pipe - in a wraparound configuration - precools air entering the cooling coil and provides free reheat to air leaving the coil. The resul
3、t: excellent humidity control without over cooling, minimal refrigeration load and maximum energy savings. And with outdoor air tamed, controlling the indoor climate is no sweat. Greenhecks model ERT is just one of a wide range of energy recovery solutions for schools, office buildings, theaters, ch
4、urches, retail stores .wherever affordable indoor air comfort is a must. For more information, contact your Greenheck rep or visit our website today! .- . . . . -. . . . . . -. .-. . - . . Number one in air movement and control. ! I j i+- Centrifugal and Vane Axial Fans , Fans and Ventilators Energy
5、 Recovery Ventilators Dampers and Louvers Make-up Air Units Greenheck - P.O. Box 410 Schofield, WI 54476-0410 Phone (715)359-6171 - Fax (715)355-2399 Circle No. 7 on Reader Service Card or visit www.pub- ASHAEJOURNAL (ISSN 0001-2491) MISSION STATEMENT ASHRAE Journal reviews current HVAC washofcashr
6、ae,org Practical Guide Editor i Kenneth M. li, PE. I PUBLISHING SERVICES FIRST DEVELOPED in response to the energy crisis in the 1970s, Standard 90.1 is among ASHMES most significant contributions to the public. It provides minimum energy-efficiency requirements for three elements of the building:
7、(1) Light and Power, (2) Envelope, and (3) Mechanical Equipment and Systems. Ten years in the making, the importance of the 1999 edition is reflected in two Publishing Services Manager Barry Kurian full public reviews and a partial public review. More than 80,000 comments were received fi-om 3,900 p
8、eople. Most came from competing interests, such as the gas and electric industries. It was the Standard 90.1 Committees job to resolve as many as possible. “It was probably the biggest, most challenging, most aggravating, most Production Assistant Jayne Jackson Graphic Design Tracy Becker ADVERTISIN
9、G Advertising Sales Manager Chuck Pennscott satising thing Ive ever worked on,” says Ron Jarnagin, who chaired the Standard 90.1 committee from 1995-1999. I , cpennscottashrae.org t Arlvr.r+icin- Prndiirtinn Manaver THE 1999 EDITION is the first ASHRAE standard to be written in code- enforceable lan
10、guage. This enables faster adoption by state and local jurisdictions. The 1999 edition also: Includes true prescriptive options for-building envelope requirements.-This - makes compliance easier, and simplifies the work of designers and code officials. Has a separate User Manual that was released at
11、 the same time as the new edition of the Standard. Includes international weather data and an SI edition. Is reorganized for clarity. More complex, less used information is presented Has simplified approach for mechanical systems for commercial buildings 5,000 later in chapters. fi2 (500 m) and smal
12、ler. All compliance information is contained on two pages. STANDARD 90.1 is on continuous maintenance, so its updated continuously andrepublished every three years. The 2001 edition is the current standard and the Standard 90.1 Committee is working on the 2004 edition. The 1999 edition will serve as
13、 the US. baseline for energy efficiency until the U.S. Secretary of Energy determines theres been a “comprehensive revision.” The 2001 version, however, will be referenced in the National Fire Protection Association (NFPA) consensus code set. This version is expected to be referenced in the Internat
14、ional Energy Conservation Codes (IECC) model building code a-. , -.-.-.-.a . .-.- . .- I Irene F. Eggeling j ieggelingashrae.org I ! CIRCULATION i Circulation Manager f 8 Phyllis Maurer 1 ASHRAE OFFICERS : President Donald G. Colliver, Ph.D., PE. : President-Elect Richard H. Rooley, FREng : Treasure
15、r B Ron Vallort, PE. I Vice Presidents Julian R. de Bullet I Stephen W. Ivesdal Kent Peterson, PE. 1 Terry Townsend, Ph.D., PE. I Secretary ewe five New York bouroughs BOMA Opposes Mol/Mildew Rules WASHINGTON, D.C.-The Building Owners and Managers Association (BOMA) International has approved a posi
16、tion statement that opposes initia- tives by federal, state and local authori- ties to write model building codes and standards regulating mold and moisture. The position statement was adopted by the Board of Governors at the BOMA Annual Convention on June 23-25. It opposes disclosure requirements i
17、n the sale of commercial properties that BOMA says could confuse consumers or expose sellers and lessors to unpre- dictable liability. “Unlike many other known toxins, such as lead, mercury or cadmium, there are no standards for levels of mold toxic- ity and no known permissible mold ex- posure limi
18、ts for the indoor environ- ment,” said BOMA President Larry Soehren. “We as an industry must address this issue in a way that is reasonable, fair and, most importantly, effective.”. Profits Shrink for Consulting Firms NATICK, Mass.-After two years of double-digit profit margins, architecture, engine
19、ering, planning, and environmen- tal consulting firms saw profits shrink by more than 2% in the most recently completed fiscal year, according to a newly published survey by ZweigWhite (available at ). The survey says median net pre-tax, pre- revenue less subconsultants and reimburs- able expenses)
20、was 8.8% in 2001, down from 10.6% in 1999 and 1 I. 1 % in 2000. Ian Rusk, CFO at ZweigWhite, said things are looking up so far this year. Median pre-tax, pre-bonus profits on net service revenue were 10.7% in February and 12.2% in March. “This would seem to indicate that profit margins have bonus pr
21、ofit on net service revenue (gross picked up over the first quarter: he said I performance pleated -y- - 8 a! il ! air filter offers a higher filter performance than 1 KI pieat offers superior particulate size I efficiency and low pressure drop .MERV 11 Tested PerASHRAE regular pleated filters The M
22、R- f P I, , Standard 52.2. * _ . . A 6 C Temperature (“0 80 60 77 DX Active Moisture (grlib) 124 77 57 Airflow (scfm) 2,000 2,000 2,000 cooling Desiccant Coil Wheel D 98 144 2,000 I 2,000 cfm unit W Us Figure 3: Recent commercial innovations for ventilation dehumidification. (“Cl 26.7 15.6 25.0 36.7
23、 glkg) 17.7 11.0 8.1 20.6 (Us) 944 944 944 944 TT Exchanger Avoiding any need for exhaust air, this design uses an air-to- air heat exchanger to pre-cool and reheat the outdoor air that is dried with a mechanical dehumidifier. Heat pipes, coil run- around loops and plate-type heat exchangers have be
24、en used for this purpose. Because of the second pass through the heat exchanger, this equipment delivers air closer to the indoor temperature than the Type 1 configuration. Also, since the Type 2 units 24 performance does not require dry exhaust air, this equipment can dry the ventilation air any ti
25、me the humidity rises above setpoint. So, it is often configured to control humidity rather than just moderate the extreme as in the Type 1 configuration. Also, the supply fan must overcome the friction oftwo passes through a heat exchanger. This friction, plus the extra dehu- midification work for
26、more hours of the year, sometimes makes this equipment more costly to operate. Of course, its usually doing more work than the Type 1 system. August 20021ASHRAE Journal After years of research and development, Munters has created the perfect efficiency marriage. Munters Humidity Control Unit (HCU) c
27、ombines direct expansion cooling with active desiccant technology and the result is the perfect humidity control solution for the conditioning of outside ventilation air. Munters maximizes the operating conditions of these two technology solutions making Munters HCU compact and very efficient. Ail o
28、f the energy required for the humidity control operation is recycled from the cooling components improving the efficiency of the mechanical system. As a result, operating costs are reduced. Ventilation air treated by HCU is delivered to the space at or below space neutral conditions. The unit can be
29、 operated as a stand-alone system or used for outside air pretreatment to offload and downsize standard air conditioning units. The HCU includes a microprocessor ensuring proper conditions in the space. A digital temperature and humidity controller operates the unit. With the use of an external wire
30、less modem, remote monitoring and diagnostics is an option that streamlines maintenance. To find out more about Munters HCU, call 1-800-229-8557. Munters Corporation Dehumidification Division 16900 Jordan Road Selma, TX 78154 Tel (210) 651-5018 or Fax (210) 651-9085 drycoolinfo Circle No. 10 on Re
31、ader Service Card or visit www.pub- The Humidity Expert ASHRAE Journal DRY BULBTEMPERATURE -F , - 70 , ?,$ zo 2s Figure 4: Using TMyobservations to determine the mode (the most typical) outdoor moisture content when the dry-bulb temperature is 75F (24OC): IuPe 3 : Two-staue DesiccantlMechanical Dehu
32、mldl fie This two-stage equipment uses the condenser heat from a mechanical dehumidifier to reactivate an active desiccant wheel. First, ventilation air is precooled and partly dried by the mechanical dehumidifier. Then the air is dried more deeply and also reheated by the desiccant wheel. This arra
33、ngement uses both technologies at favorable points of performance. Mechanical dehumidifiers are most effective and economical at higher inlet conditions, and desiccants gain advantages at cooler and more saturated conditions. Also, in this arrangement the heat normally wasted in a mechanical dehu- m
34、idifier is put to productive use drying the desiccant wheel. Further, the design allows several stages of capacity modulation. The mechanical dehumidification section has two compressors, which are staged, and the desiccant wheel can be stopped while the mechanical DH section continues to operate. T
35、his allows a close match between changing loads and energy use. Finally, the air leaves the unit much closer to the indoor air temperature than is the case with desiccant-only equipment. So, the overall performance of this configuration is quite impressive in terms of all-weather deep-drying capacit
36、y as well as low operating costs. 26 Limitations of this configuration include the fact that the supply air temperature changes according to how much drying the desiccant wheel does. So the leaving air temperature from this equipment is neither constant nor controllable. Evaluating Ventilation Dehum
37、idifiers In commercial HVAC, the needs are very diverse, and so are the equipment offerings. Any comparison between competing offerings will be specific to a particular set of economic and geographic circumstances. The authors would suggest that, at the very least, the vendors should be willing to p
38、rovide the designer with the answers to these questions: What does the unit cost? How does it perform at peak dew-point design? (How much moisture will it remove from the ventilation air and from the building itself?) What is the performance at the more common part-load condition? How much energy do
39、es it use at part-load condition? The units price is obviously important. Its moisture removal is equally so, and is useful to note that the performance questions August 20021ASHRAE Journal Dehumidification Unit Cost (2,000 cfm or 944 LA) Indoor Control Point (“F, gr/lb) 2% Dew Point Pf; gr/ib) Dry
40、air outlet (“F, gr/lb) Moisture removed from air (Ibh) Moisture removed from bldg (lblh) Total energy (kWlh) LPL (Part-Latent-Load) Condition Dry air outlet (OF, gr/lb) Moisture removed from air (Ibih) Moisture removed from bldg (Iblh) Total energy (kWh) Indoor Control Point (“C. glkg) 2% Dew Point
41、PC, gkg) Dry air outlet (“C. g/kg) Moisture removed from air (kg/h) Moisture removed from bldg (kg/h) Total energy (kWh) LPL (Part-Latent-Load) Condition Dry air outlet (“C, gkg) Moisture removed from air (kgh) Moisture removed from bldg (kglh) Total energy (kWlh) Chicago, IL Phoenix, A2 Miami, FL R
42、Worth, TX Atlanta, GA Honolulu, Hi $10,000 s10,oM) %1O,Ow) $10,000 J10,MM $10.000 75 65 75 65 75 65 75 65 75 65 75 65 82 138 81 126 80 124 79 116 80 115 85 104 80 71 79 62 78 60 77 54 77 55 77 51 86 82 82 80 77 68 -8 4 6 14 13 18 9.9 9.9 9.8 9.8 9.8 9.9 75 116 75 114 75 114 75 93 75 88 75 35 76 52 7
43、6 50 76 50 80 53 79 49 NIA 82 82 82 51 50 NIA 17 19 19 18 21 NIA 9.8 9.8 9.8 5.9 5.9 N/A 24 9.3 24 9.3 24 9.3 24 9.3 24 9.3 24 9.3 28 19.7 27 18.0 27 17.7 26 16.6 27 16.4 29 14.9 27 10.1 26 8.9 26 8.6 25 7.7 25 7.9 25 7.3 39 31 31 36 35 31 -3 2 .3 6 6 8 9.9 9.9 9.8 9.8 9.8 9.9 24 16.6 24 6.3 . 24 16
44、.3 24 13.3 24 12.6 24 5.0 24 1.4 24 7.1 24 7.1 27 7.6 26 7.0 N/A 31 31 31 23 23 NIA 8 9 9 8 9 N/A 9.8 9.8 9.8 5.9 5.9 NIA Figure 5: A two-stage desiccant/mechanical ventilation dehumidifier at 2% dew-point des&, and part-load conditions. really have two parts. Ventilation dehumidifiers remove moistu
45、re from incoming air. Also, at some outdoor conditions, they de- liver dry air somewhat below the indoor design dew point, dehu- midiing the space as well. However, that is not always the case. Under other conditions, the unit may not dry the ventilation air deeply enough to remove any moisture from
46、 the building. The vendor needs to quantifi moisture removalporn the space itself as well as the delivered air temperature. With that information, the designer can adapt the rest of the system to take advantage of the dehumidifiers strengths and compensate for any limitations. Further, although the
47、energy use at peak design is useful in- formation, the more important figure is the pical hourly en- ergy use. In other words, the energy consumed for 98% of the operating hours instead of for just 2% of them. When possible, an 8,760-hour building simulation will provide the best esti- mates of oper
48、ating costs. However, not all projects have design budgets that justi such analysis. Another approach is to have the vendor calculate the performance and energy use at some “off-peak” condition, which may be more typical of the bulk of the operating hours than its performance at the peak load. As fa
49、r as the authors are aware, no general agreement exists on what constitutes a reasonable and consistent off-peak con- dition with which to test dehumidifier performance and en- ergy use. The authors have a suggestion that other designers may wish to consider. Part-Load Dehumidification Design Conditions Chapter 27 of the 2001 ASHRAE Handbook-Fundamen- tals
