HVAC SYSTEMS ALL OF THE EQUIPMENT NECESSARY TO PROVIDE THE DESIRED ENVIRONMENTAL CONDITIONS IN A BUILDING OR ITS PARTS

Transcription

1 HVA SYSTEMS ALL OF THE EQUIPMENT NEESSARY TO PROVIDE THE DESIRED ENVIRONMENTAL ONDITIONS IN A BUILDING OR ITS PARTS FATORS TO BE ONSIDERED WHEN SELETING A SYSTEM 1. PERFORMANE 2. FIT INTO AVAILABLE SPAE 3. GIVE THE OWNER THE BEST OMBINATION OF: A. FIRST OST B. OPERATING OST. RELIABILITY HVA SYSTEMS PRIMARY SYSTEMS: TO ONVERT THE ENERGY IN A FUEL OR ELETRIITY TO THERMAL ENERGY FOR HEATING OR OOLING (BOILERS, HILLERS, ET.) SEONDARY SYSTEMS: TO DISTRIBUTE FRESH AIR, HEATING AND OOLING TO THE SPAES IN A BUILDING (DUTS, FANS, PIPES, PUMS, DAMPERS, ET.) 1

2 PRIMARY SYSTEMS - ONVENTIONAL SYSTEMS (BOILERS, FURNAES, HILLERS, OOLING TOWERS) - HEAT PUMP SYSTEMS (AIR-SOURE, GROUND SOURE) - O-GENERATION SYSTEMS - SOLAR THERMAL (AIR AND WATER BASED) - PV, BUILDING INTEGRATED PV (BIPV) - THERMAL STORAGE 2

3 SEONDARY SYSTEMS: 1. ALL-AIR SYSTEMS A. SINGLE PATH SYSTEMS (SZV, V REHEAT, VAV, VVVT) H B. DUAL PATH SYSTEMS (DUAL DUT) H 2. AIR-AND-WATER SYSTEMS 2, 3 OR 4-PIPE SYSTEMS, FAN-OIL SYSTEMS 3. ALL-WATER SYSTEMS UNIT VENTILATORS, FAN-OILS, BASEBOARD ONVETION 4. PAKAGED (UNITARY) SYSTEMS WINDOW AIR ONDITIONERS, ROOF-TOP SYSTEMS 3

4 ALL-AIR SYSTEMS 1. SINGLE-ZONE ONSTANT VOLUME (SZV) MASS FLOW RATE BALANES 4

5 H 3-WAY DIVERTING ONTROL VALVES HWS HWR WS WR T 5

6 H 3-WAY MIXING ONTROL VALVE HWR HWS H 2-WAY ONTROL VALVE (could be on the supply or return side) HWR HWS 6

7 2. ONSTANT VOLUME - TERMINAL REHEAT 7

8 DISRIMINATOR ONTROL: TO MINIMIZE REHEAT S/A RH RH RH ZONE 1 ZONE 2 ZONE 3 R/A THE S/A TEMP IN THE MAIN DUT IS INREASED UNTIL THE VALVE ON THE REHEAT BOX OF ONE ZONE IS FULLY LOSED. 8

9 3. ONSTANT VOLUME MULTI-ZONE DISRIMINATOR ONTROL: 1. INREASES THE OLD DUT TEMP UNTIL THE HOT DUT DAMPER OF ONE ZONE IS FULLY LOSED 2. DEREASES THE HOT DUT TEMP UNTIL THE OLD DUT DAMPER OF ONE ZONE IS FULLY LOSED OBJETIVE: TO MINIMIZE MIXING 9

10 4. ONSTANT VOLUME BY-PASS MULTI- ZONE NO NEED FOR DISRIMINATOR ONTROL! 10

11 5. ONSTANT VOLUME DUAL DUT DISRIMINATOR ONTROL: 1. INREASES THE OLD DUT TEMP UNTIL THE HOT DUT DAMPER OF ONE ZONE IS FULLY LOSED 2. DEREASES THE HOT DUT TEMP UNTIL THE OLD DUT DAMPER OF ONE ZONE IS FULLY LOSED OBJETIVE: TO MINIMIZE MIXING 11

12 6. VARIABLE AIR VOLUME (VAV) 12

13 S/A TO ZONES (~ 55 F) VAV BOX T S/A HWS BASEBOARD HEATING UNIT HWR OPERATING SEQUENE: - AT FULL LNG LOAD: VAV BOX FULL OPEN HTNG VALVE LOSED - AS LNG LOAD DEREASES: VAV BOX MODULATES LOSE HTNG VALVE REMAINS LOSED - AS LNG LOAD FURTHER DEREASES: VAV BOX WILL REAH ITS MIN POSITION AND WILL NOT LOSE ANY FURTHER - ONSET OF HTNG LOAD: HTNG VALVE MODULATES OPEN VAV BOX REMAINS AT MIN POSITION 13

14 SUPPLY FAN TRAKING (VAV SYSTEMS) (TO REDUE FAN POWER ONSUMPTION) - S/A AND R/A FANS ARE VARIABLE VOLUME FANS (VARIABLE SPEED OR VARIABLE INLET VANES) - R/A FAN MUST TRAK THE S/A FAN (MEASURE THE S/A FLOW RATE AND MATH THE R/A FAN OPERATION TO MATH THE S/A FLOW RATE - S/A FAN IS ONTROLLED BY A STATI PRESSURE SENSOR AT THE FAR END OF THE DUT SYSTEM 14

15 AIR-AND-WATER SYSTEMS - HEATING AND OOLING PERFORMED BY BOTH AIR AND WATER SUPPLIED TO THE SPAE - ADVANTAGES: LESS SPAE REQ'S SINE c p,water >> c p,air PUMPING POWER << FAN POWER - QUANTITY OF AIR SUPPLIED = VENTILATION REQMNT - IF THIS AIR IS EXHAUSTED DIRETLY AT THE ZONE LEVEL => NO R/A SYSTEM NEEDED 15

16 FAN OIL SYSTEM (VENTILATION DUT NOT SHOWN) 16

17 1. 2-PIPE SYSTEMS (HANGEOVER) - ONLY TWO PIPES IN THE WATER DISTRIBUTION IRUIT: ONE FOR SUPPLY, ONE FOR RETURN - THE OIL IS USED SEASONALLY FOR HEATING OR OOLING - ALL OILS IN THE BUILDING OPERATE EITHER AS HEATING OR AS OOLING OILS => THEREFORE, THIS SYSTEM IS NOT FLEXIBLE FOR MIXED DUTY (SOME SIMULTANEOUS HTNG AND LNG POSSIBLE USING PRIMARY AIR) BOILER HILLER FROM BUILDING TO BUILDING OIL 17

18 2. 4-PIPE SYSTEMS A) SEPARATE OILS AT EAH ZONE TERMINAL BOX WR WS HWR H HWS T 18

19 B) OMMON OIL T HWR HWS WR 2-POSITION AUTOMATI DIVERTING VALVE (EITHER TO HILLER OR HOT WATER RETURN LINE) WS SEQUENE VALVE => ONTROLS HOT AND HILLED WATER SUPPLY SELETIVELY AND PROPORTIONALLY, BUT DOES NOT MIX THEM 19

20 TERMINAL UNITS: - FAN OIL - INDUTION 3) 3-PIPE SYSTEMS - HOT WATER SUPPLY - HILLED WATER SUPPLY - OMMON RETURN - WASTEFUL AND SENSELESS => UNOMMON 20

21 ALL WATER SYSTEMS - FAN OIL - UNIT HEATER - BASEBOARD ONVETION NO POSSIBILITY TO PROVIDE VENTILATION, THEREFORE NOT USED ANY MORE REVERSE-RETURN PIPING SYSTEM BOILER 21

22 REVERSIBLE WATER SOURE HEAT PUMP SYSTEM ONSIDER A BUILDING WITH AN INNER ORE OPERATING IN WINTER: - THE PERIMETER ZONES WILL BE IN HEATING MODE - THE ORE ZONE WILL BE IN OOLING MODE (NO HEAT LOSS) THIS PROVIDES AN OPPORTUNITY FOR HEAT REOVERY USING REVERSIBLE WATER SOURE HEAT PUMPS. 22

23 REVERSIBLE WATER SOURE HEAT PUMP SYSTEM 23

24 HEAT REOVERY POTENTIAL - EXHAUST AIR HEAT REOVERY TO PREHEAT/PREOOL VENTILATION AIR O AIR- TO- AIR HEAT EXHANGER O HEAT REOVERY VENTILATOR O HEAT WHEEL (SENSIBLE AND SENSIBLE+LATENT) O RUN- AROUND GLYOL LOOP O HEAT PIPE O GREY WATER HEAT REOVERY - HEAT REOVERY FROM REFRIGERATION EQUIPMENT 24

25 PASSIVE SOLAR DESIGN - ORIENTATION OF LONG AXIS (E- W) - WINDOW PLAEMENT, SIZE AND TYPE - EXTERNAL SHADING - TROMBE WALL - THERMAL STORAGE - NATURAL VENTILATION/SOLAR HIMNEY - SOLARWALL - VENTILATION AIR PRE- HEATING - BUILDING INTEGRATED PHOTOVOLTAIS/THERMAL (BIPVT) 25