THE MODERN HVAC SYSTEM. J. Michael Carson P.E. Senior Mechanical Engineer Purdue University

Size: px

Start display at page:

Download "THE MODERN HVAC SYSTEM. J. Michael Carson P.E. Senior Mechanical Engineer Purdue University"

Myles Cunningham
6 years ago
Views:

1 THE MODERN HVAC SYSTEM J. Michael Carson P.E. Senior Mechanical Engineer Purdue University

2 Btu Ton Heat Gain & Heat Loss Air Handling Unit Fan Air Distribution Preheat Coil Cooling Coil Reheat Coil Double Duct Diffuser Grille Register Constant Volume VAV DOAS Chilled Beam UFAD 1

3 2

4 Physical Sciences have a long history of discovery Galileo Carrier Fahrenheit Fulton Celsius Watt 3

5 Leading to today s HVAC Engineer Their work is based on energy transfer The energy they transfer is HEAT 4

6 Heat is always moving Flows from higher energy (something hot) to lower energy (something cold) 5

7 BTU (BRITISH THERMAL UNIT) How we measure heat in America 1 BTU = 1 lb of water 1 F 6

8 QUIZ #1 If it takes one hour to heat 1 lb of water 1 F the heat transfer rate would be Circle your answer 1 Btu/Hr 1 BTH 1 BTUH Being well read engineers understand Ralph Waldo Emerson A foolish consistency is the hobgoblin of little minds 7

9 QUIZ #1 This helps you understand the HVAC engineer A foolish consistency is the hobgoblin of little minds 8

10 QUIZ #2 What was a favorite treat Washington and Jefferson served summer visitors? How could they eat ice cream in the summer of 1700 s? 9

11 ICE HARVESTING 10

12 QUIZ #3 When one ton of ice melts in one day (24 hours) what do we call the heat absorbed by that ice each hour? 1 Ton 1 Ton = 12,000 Btu/Hr 11

13 QUIZ #4 Is there such a thing as one ton of heat? No Now what did Emerson say? 12

14 HEAT GAIN & LOSS CALCULATION What makes heat? Lights People Equipment Walls & Windows Solar THE BACKBONE OF HVAC DESIGN How do we get rid of the heat? 13

15 AHU (AIR HANDLING UNIT) Fan, Cooling coil, Ductwork, Filters, Diffusers & grilles, Condensing unit, etc. Originally installed in special rooms 1950s more people wanted AC What did we do if we had multiple rooms? 14

16 1950S MULTIPLE AHUS ADVANTAGES Everybody gets AC DISADVANTAGES Exterior appearance Maintenance Noise Floor space HOW WE REMOVED THE PROBLEMS 15

17 1960 CENTRAL STATION AHU ADVANTAGES Serves many rooms Noise is isolated Localized maintenance, few pieces of equipment DISADVANTAGES One zone No outside air 16

18 1960 CENTRAL STATION AHU Energy Tips 1. No more OA than necessary ADVANTAGES Serves many rooms Noise is isolated Low maintenance Fresh air DISADVANTAGES One zone Air can t get back to the AHU 17

19 1963 CENTRAL STATION AHU Energy Tips 1. No more OA than necessary 2. Fan operation ADVANTAGES Serves many rooms Noise is isolated Low maintenance Fresh air Pressure Control DISADVANTAGES One zone Cools in winter 18

20 1965 AHU W/ ECONOMIZER Energy Tips 1. No more OA than necessary 2. Fan operation 3. Economizer operation 4. Damper operation ADVANTAGES Serves many rooms Noise is isolated Low maintenance Fresh air Pressure Control Economizer DISADVANTAGES One zone 19

21 1966 DOUBLE DUCT Energy Tips 1. No more OA than necessary 2. Fan operation 3. Economizer operation 4. Damper operation 5. Remove simultaneous heating and cooling ADVANTAGES Serves many rooms Noise is isolated Low maintenance Fresh air Economizer Room level control Flexible DISADVANTAGES Uses a lot of energy OIL EMBARGO!! 20

22 1975 SHUT-OFF VAV ADVANTAGES Serves many rooms Noise is isolated Low maintenance Fresh air Pressure Control Economizer Saves Money DISADVANTAGES Poor air quality Poor humidity control Poor temperature control SICK BUILDING SYNDROME!! 21

23 1980S VAV WITH REHEAT ADVANTAGES Serves many rooms Noise is isolated Low maintenance Fresh air Pressure Control Economizer Saves Money DISADVANTAGES No good speed control (mechanical) 1990S VFD!!!! HOW DO THEY WORK? 22

24 VFD OPERATION 30 Hz 45 Hz 60 Hz 60 Hz 23

25 VFD OPERATION 30 Hz 45 Hz 60 Hz 60 Hz 24

26 VFD OPERATION 30 Hz 45 Hz 60 Hz 60 Hz 25

27 30 Hz 45 Hz 60 Hz 60 Hz 26

28 1990S VAV REHEAT VFD BEEN THE WORKHORSE FOR 20 YEARS WHAT IS ON THE HORIZON? DOAS 27

29 DOAS 28

30 DOAS 29

31 DOAS ADVANTAGES Small AHU Small ductwork Less energy?? OFFICES, DORMS, ETC. CHILLED BEAMS DISADVANTAGES FCUs or other room level system 30

32 CHILLED BEAMS HOW DO THEY WORK? 31

33 CHILLED BEAMS 32

34 CHILLED BEAMS 33

35 CHILLED BEAMS ADVANTAGES Small AHU Small ductwork DISADVANTAGES Can take many chilled beams Careful temp control UFAD 34

36 UFAD 35

37 UFAD 36

38 UFAD ADVANTAGES Small AHU Small ductwork Less energy?? DISADVANTAGES Careful construction details Careful temp control 37

39 THE END OF THE MODERN HVAC SYSTEM J. Michael Carson P.E. Senior Mechanical Engineer Purdue University

HVAC Controls Upgrade FPT: Scheduling, Override & Night Setback; End to End ( )

HVAC Controls Upgrade FPT: Scheduling, Override & Night Setback; End to End ( ) REQUIRED SEQUENCES CONTROLS/FEATURES: Indicate that the specific feature is installed and record the date it was verified to work correctly. Indicate NA if not required by grant. Installed? Date Tested