Objectives • Discus final project • Load calculation Final Project Group 1: Heather Smith Tommy Beales Matt Leos Group 5: Nick Williams Stephen Mathai Kevin Carbonnier Group 2: Patrick Gorman Kenny Greaves Matt McCarthy Group 6: Marcus Allen Josh Atkins Matt Larson Group 8: Marwa Zaatari Megan Gunther Elena Nirlo Individual projects Neil Woodson Wesley Cole Group 9: Gregory Arcangeli Andrew Hoisington Adam Keeling Sami Kolahdoozan Gautam Salhotra Group 3: Sarah Johnson Jocelyn Citty Tobias Nilsson Group 4: Zaid Arzate Brian Burcham Justin Barrett Group 7: Stephen Fridley Shahrukh Gaziani Margaret Lawson Project topics 1) VAV system design • • Fresh air requirements and recirculation rate calculation Selection of zonal and central HVAC components based on cooling and heating load components • • • • For zones: VAV boxes, reheaters, reheater plumbing For whole system: AHU and components, chiller & cooling tower, boiler, and electric power requirement Control description – sequence of operation Heat recovery system and or economizers 2) DOAS system design • • Fresh air requirement and split between air and hydronic loads (sensible and latent cooling loads) Selection of zonal and central HVAC components based on cooling and heating load components • • • • For zones: fan coils and plumbing For whole system: AHU and components, chiller & cooling tower, boiler, and electric power requirement Control description – sequence of operation Heat recovery system and or economizers Project topics 3) Cooling systems and distribution • • • • Air cooled condenser vs. water cooled condenser (energy performance analysis) Design of plumbing systems for campus and pumping stations Control of centralized system Saving with variable speed pumps 4) Duct Design (in Revit) • • • • • - Diffuser selection, design of local and central duct system components - Spacing issues and difference between round and square ducts - Difference between manual calculation and calculation by Revit (for a section of the duct system) - Balancing and fan selection - Life cycle analysis and optimization (fan power consumption vs. system cost) DOAS with multi-split systems Fresh air? DOAS fresh air configurations DOAS fresh air configurations Cooling and Heating Loads (For Project) Commercial building »Zone orientation Cooling and Heating Loads (For Project) »Cooling and heating load for each zone and whole building: »Fresh air requirement based on number of occupants: »To provide acceptable IAQ in the building, ventilation » system supply minimal amount of »fresh air is in all spaces (except plenums) »that produce 0.2 ACH. Cooling Load Calculation • Mostly computer based • Handouts for manual calculation • http://www.ce.utexas.edu/prof/Novoselac/classes/ARE346N/Handouts/heatloss_table_2008.doc • http://www.ce.utexas.edu/prof/Novoselac/classes/ARE346N/Handouts/ASHRAE_%20Gains_Calculation_Tables.doc Heat Recovery Sensible and Enthalpy wheel Economizer Economizer (fresh air volume flow rate control) »Controlled device is damper »damper »fresh » air » » »mixing »recirc. » air »T & RH sensors - Damper for the air - Valve for the liquids Economizer – cooling regime How to control the fresh air volume flow rate? »If TOA < Tset-point → Supply more fresh air than the minimum required »The question is how much? »% fresh air »Open the damper for the fresh air »and compare the Troom with the Tset-point . »Open till you get the Troom = Tset-point »If you have 100% fresh air and your » still need cooling use cooling coil. »100% »Minimum for » ventilation »What are the priorities: » - Control the dampers and then the cooling coils or » - Control the valves of cooling coil and then the dampers ? »Defend by SEQUENCE OF OERATION » the set of operation which HVAC designer provides to the automatic control engineer Economizer – cooling regime »Example of SEQUENCE OF OERATIONS: »If TOA < Tset-point open the fresh air damper the maximum position »Then, if Tindoor air < Tset-point start closing the cooling coil valve »If cooling coil valve is closed and T indoor air » till you get T indoor air = T set-point » »Other variations are possible < Tset-point start closing the damper Desiccant wheel »Figure 3 – A desiccant-based cooling system combined with regenerative heat exchanger, vapor compression cooling, and evaporative humidifier (hybrid system).