Environmental Systems for Buildings 1
Environmental Systems for Buildings 1 AREN 3050
Popular in Course
Popular in Architectural Engineering
This 8 page Study Guide was uploaded by Dixie McClure II on Thursday October 29, 2015. The Study Guide belongs to AREN 3050 at University of Colorado at Boulder taught by Michael Brandemuehl in Fall. Since its upload, it has received 52 views. For similar materials see /class/231862/aren-3050-university-of-colorado-at-boulder in Architectural Engineering at University of Colorado at Boulder.
Reviews for Environmental Systems for Buildings 1
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/29/15
AREN 3050 ENVIRONMENTAL SYSTEMS FOR BUILDINGS FALL 2005 l Psychrometrics a Moist air has a dry bulb temperature of 80 F and a wet bulb temperature of 67 F What is the enthalpy at sea level What is the enthalpy at 5000 ft above sea level hsealevel 315 Btulb h5ooo b A building zone is maintained at 76 F dry bulb and 50 RH The zone has a sensible cooling load of 40000 Btuhr and total cooling load of 50000 Btuhr The supply air temperature delivered to the zone is 55 F Assuming that the return air from the zone is at the same conditions as the zone air what air ow rate cfm is required qsen 40000 Btuhr qsen Tra Tsa CFM 40000109 X 21 CFM 1747 cfm c In winter 10000 cfm of ventilation air for a building at sea level is heated and humidi ed The air enters at 35 F and 30 RH and is conditioned to 70 F and 30 RH How much energy is required to heat and humidify the air hin 97 Btulb hout 220 Btulb q 445 CFM hout hiquot q 445 X10000 x 220 97 q 547350 Btuhr d What if the dew point of air at 70 F and 30 RH at sea level Tdewpoint 37 F FINAL EXAM REVIEW PAGE 1 11 DECEMBER 2005 AREN 3050 ENVIRONMENTAL SYSTEMS FOR BUILDINGS FALL 2005 2 Comfort a How much heat is generated by a 6 ft tall 180 lb man performing basic office work qMMETxADx184 MET 12 AD m0425 H0725 AD 0657 1800425 60725 219 ft2 q 483 Btuhr b A company executive sits in a comer office on a hot summer day wearing a clothing ensemble with a thermal resistance of 05 clo Due to radiation and heat transfer through the exterior walls the mean radiant temperature in the office is 80 F What is an appropriate air temperature to ensure comfort Top 05 x Tair MRT For comfort with a clothing level of 05 Using either Fig 26 or Fig 221 range of Top 73 to 785 then range of Tai 66 to 77 F FINAL EXAM REVIEW PAGE 2 11 DECEMBER 2005 AREN 3050 ENVIRONMENTAL SYSTEMS FOR BUILDINGS FALL 2005 3 Heating Loads a What is the design heating load associated with in ltration for a 2000 ft2 house in Boulder with a ceiling height of 8 ft and an indoor temperature of 70 F if the in ltration rate is 035 ACH qin l X X VOI X Tindoor Toutdoor Vol 2000 x 8 16000 ft3 From Table 116 Toutdoor 3 F qin 0018 x 035 X16000 x 67 qin l 6754 Btuhr b What is an approximate RValue of a 075in airspace between a brick facade and an 39nsulated wall structure for heating load calculations Use Table 35 Horizontal heat flow The airspace is outside the insulation giving a mean airspace temperature close to outdoor temperature assume to be in the range of 10 30 F If the wall is insulated most of the temperature difference between indoor and outdoor will be across the insulation giving a relatively small AT across air gap assume 10 F Without any special reflective surfaces effective emittance is 082 Then Rairspace is approximately 10 12 hr ft2 FBtu c What is rate of heat transfer through a typical 3ft by Sft wood framed window haVing double glazing with a l2in air gap if the indoor temperature is 70 F and outdoor temperature is 20 F q Tindoor Toutdoor From Table 425 ID 5 woodvinyl operable U 051 Btuhr ft2 F q O51x15x70 20 q 383 Btuhr d What is the RValue of an 8in thich perlite lled normal weight concrete block From Table 36 R 2 hr ft2 FBtu FINAL EXAM REVIEW PAGE 3 11 DECEMBER 2005 AREN 3050 ENVIRONMENTAL SYSTEMS FOR BUILDINGS FALL 2005 4 Cooling Loads a What is the CLTD for a darkcolored roof in Detroit Use Table 427 for CLTD To get CLTD need design temperature and daily range from Table 116 Tdesign 87 F Range 204 F medium range M CLTD 39 F b Consider the attic of a residential building The ceiling measures 50 ft by 40 ft and the roof has a 22 pitch The ceiling has an RValue of R30 The dark shingled roof and its associated gable endwalls have an RValue of R2 For cooling load calculations in Detroit what is the cooling load contribution of heat transfer through the ceiling q UcombAceil Ucomb Ra Ace 2000 ft2 Ar Aroof 2 Aend 2000cos22 2 x 40 x 20 tan22 2 Ar 2157 323 2480 ft2 AceiIIAr 0806 From Table 435 with typical ventilation of 004 cfmft3 R3 21 Ucomb 130 21 20806 00297 Btuhr ft2 F From a CLTD 39 F q 2314 Btuhr c What is the cooling load contribution due to a typical unshaded westfacing 3ft by 5ft wood framed window in Detroit haVing double glazing with a l2in air gap How much would it decrease if curtains were added on the inside q GLF x A From Table 429 assuming regular double pane no curtains design temperature of 87 F GLF 774 Btuhr ft2 q 1161 Btuhr with curtains GLF 404 Btuhr l t2 q 606 Btuhr d When calculating cooling loads what is an appropriate heat gain due to equipment lights in the kitchen area of a residence From Table 418 assume 1600 Btuhr FINAL EXAM REVIEW PAGE 4 11 DECEMBER 2005 AREN 3050 FMVInnMMFmAI FALL 2005 s Sula Pesmeh and sheathg 2 what ume MST ml the sun msappearhehma the meuhtams eh chnstmas dew I III t standard ttme surmme e E 7403 7 hat staneatettme 3 amen u 3 an pm h Huwmany degrees suuLh ufdue west wtu the sun he when the sun atps behmd the 7 muuntams m a abuve Frum chant aztmuth ang e 48 sun ts anquot 7 48 42 suuth uf due W251 Hm EXAM R EvtEW PAGE 5 M DECEMBERZUUS AREN 3050 ENVIRONMENTAL SYSTEMS FOR BUILDINGS FALL 2005 6 Ducts and Diffusers a What is the pressure drop through a 6in round duct 50 ft long that terminates with a boot diffuser type G shown in Fig 713 with an air ow of 200 cfm boot G has 30 ft effective length Leg 50 3080ft From Fig 728 with 6 duct and 200 cfm pressure drop per 100 030 inWG pressure drop 030 x 80100 024 inWG b A singleperson of ce measures 12 ft by 12 ft with 8 ft ceilings The loads in the room require an air or of 150 cfm Select a high sidewall diffuser from the performance data in the teXt that would be appropriate for this room Place one diffuser on one wall Characteristic length is 12 ft Select terminal velocity of 100 fpm For office noise criterion must be NC lt 35 Need diffuser that will through 150 cfm of air a distance of 12 ft with a terminal velocity of 100 fpm and NC lt 35 From Table 811 a diffuser with core area of 018 ft2 will have a through at 100 fpm between 8 16 ft depending on deflection angle with NC 22 FINAL EXAM REVIEW PAGE 6 11 DECEMBER 2005 AREN 3050 FNVIHUNMFNTAI ASHRAE PSYCHROMEmIc mum No1 Maamuaumnmli um FALL 2005 um 2m mwssaruzawav mum 1952 m mama usmm nsmmm ma untannmnmuo museum SEA LEVEL W L Hm EXAM PEMEW summmmsmm may PAGE 7 11 DECEMBER 2005 AREN 3050 FNVIHUNMFNTAI SYCHROMETRXC cmm NO 4 mmu EIIPEHAle Imam mum n quotmung m mmzs nmzmm wvmm 19 Scam a m mxmvssnmm mumwmmmmmua 5000 FEET FALL 2005 Hm EXAM EMEW ENV39NALOVJmnEk voanaFniVmi PAGE 8 11 DECEMBER 2005
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'