Objectives

1
Objectives

• Propose topics for the final project
• Learn about VAV systems

2
Project

• Design problem
• .
• Research problem
• .

3
Enthalpy wheel
4
Couple chiller and cooling tower
Cooling tower
TCTS
TCTR
Weather parameters
P
- Find COP for several weather condition

• Use nonlinear equation
• solution methods

TCWS
TCWR
Q
5
HVAC Control

• Economizer (fresh air volume flow rate control)

fresh air
filter
cooling coil
heating coil
filter
steam humidifier
damper
fan
mixing
6
Sequence of operation(ECJ research facility)
Control logic Mixture in zone 1 IF ((
TMltTSP) (DPTMltDPTSP) ) heating and
humidifying Heater control IF (TSPgtTRA)
increase heating or IF (TSPltTRA) decrease
heating Humidifier IF (DPTSPgtDPTRA) increase
humidifying or IF (DPTSPltDPTRA) decrease humid.
Mixture in zone 2 IF ((TMgtTSP)
(DPTMltDPTSP) ) cooling and humidifying Cool.
coil cont. IF (TSPltTRA) increase cooling or IF
(TSPgtTRA) decrease cooling Humidifier IF
(DPTSPgtDPTRA) increase humidifying or IF
(DPTSPltDPTRA) decrease hum. Mixture in zone 3
IF ((DPTMgtDPTSP) ) cooling/dehumidifying and
reheatin Cool. coil cont. IF (DPTSPltDPTRA)
increase cooling or IF (DPTSPgtDPTRA) decrease
cooling Heater control IF (TSPgtTRA) increase
heating or IF (TSPltTRA) decrease heating
7
Fan
Biomedical Engineering (BME) Building
Duct Optimization
Ducts
Supply
Return
In-Take air
Exhaust
8

• 3D model Biomedical Engineering (BME) Building

9

• 3D model Biomedical Engineering (BME) Building

10

• 3D model Biomedical Engineering (BME) Building

11
Life Cycle Cost Analysis

• Engineering economics

Option A
Option B
12
VAV Example

• One system
• Multiple Spaces/Zones
• - VAV box for each space/zone

• http//www.trane.com/commercial/library/vol242/v24
  b6.asp

13
VAV System Terms Equations(you can find them
in ASHRAE Standard 62)

• Fraction of minimum outdoor air in space/zone
  supply air
• Xi VOAi / VSAi
• Critical space
• Space with maximum Xi , Zmax(Xi)
• Fraction of outdoor air in system supply air
• X sum(VOA ) / sum(VSA)
• Required Fraction of outdoor air
• YX/(1X-Z)

14
Example Solution
Space1 Space 2 Space 3 Space 4
VSA
VOA
Xi
X
Z
Y
15
Other Issues Related to VAV

• Fan control
• Minimum supply air
• Occupancy sensors

16
DOAS System

• www.doas.psu.edu

17
DOAS with multi-split systems
Fresh air?
18
DOAS fresh air configurations
19
DOAS fresh air configurations
20
Project
Commercial building

• Zone orientation

21
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.

22
Cooling load calculation

• Mostly computer based
• Handouts for manual calculation
• http//www.ce.utexas.edu/prof/Novoselac/classes/AR
  E346N/Handouts/heatloss_table_2008.doc
• http//www.ce.utexas.edu/prof/Novoselac/classes/AR
  E346N/Handouts/ASHRAE_20Gains_Calculation_Tables.
  doc
• The most important issues