Objectives

• Select project topics

• Review for exam

• Learn about DOAS systems

Final ProjectGroup 1:

Heather SmithTommy BealesMatt Leos

 

Group 2:

Patrick Gorman

Kenny Greaves

Matt McCarthy

 

Group 3:

Sarah Johnson

Jocelyn Citty

Neil Woodson

 

Group 4:

Zaid Arzate

Brian Burcham

Justin Barrett 

Group 5:

Nick Williams

Stephen Mathai

Kevin Carbonnier

Group 6:

Marcus Allen

Josh Atkins

Matt Larson

Group 7:

Stephen Fridley

Shahrukh Gaziani

Margaret Lawson

Group 8:

Marwa Zaatari

Megan Gunther

Elena Nirlo

 

Group 9:

Gregory Arcangeli

Andrew Hoisington

Tobias Nilsson

Individual projects

Wesley Cole

Adam Keeling

Sami Kolahdoozan

Gautam Salhotra

Project topics1) 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 topics3) 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)

Course Exam

• This Thursday (April 21) 9:20 am

• Same classroom

• 1.5-hour exam

• Cheat sheets • Questions: all problems

• (short but comprehensive)

Course Exam

• Next Thursday (April 15) 7 pm

• Same classroom (ECJ 7.208)

• 2.5-hour exam

• Open book open notes• All problem types of questions

• (short but comprehensive)

Objectives

• Finish the pumps and plumbing systems

• Discuss the final project

Review for the Exam

• Should be able to do all calculations associated with lectures as well as HWs• Problems may deal with context

• i.e. Explain how thermal conductivity influences fin efficiency? Holding all other parameters equal, how important is increasing the thermal conductivity

Psychrometrics and Processes (7 & 8)

• Know all parameters and their location/orientation on a psychrometric chart

• Be able to look up conversions of parameters on a psychrometric chart and with calculations

• Use protractor to calculate SHR and ΔW/Δh

• Plot processes on a chart for real buildings• List what is held constant for different processes

• Describe processes in AHUs in psychrometric chat

Direct Contact (10)

• Purpose of cooling towers

• Psychrometrics

• Describe how a cooling tower works

Cycles (3), Refrigerants (4)

• Describe Carnot cycle and components• Understand constant variables for each component

• List, describe, and calculate inefficiencies

• Use figures, refrigerant tables and equations for different substances

• List important parameters for refrigerant selection/differentiation

Heat Exchangers (11)

• Differentiate types

• Calculate ε, and UA, etc.

• Complete broad analysis• Which m is larger, which Δt is larger?

• Within and between heat exchangers

Heat Exchangers (11)

• Calculate and compare different thermal resistances

• Describe influence of key factors

• Integrate different parameters/resistances

• Manipulate UA equation

• Describe differences for wet and dry heat exchangers

Diffusers, Duct Components (18)

• Select diffusers• Define all terms on manufacturer data sheets

• Calculate pressure drop of:• Straight duct• Duct fittings• Components (coils, VAV boxes, dampers, etc.)

• Differentiate fans and describe fan curves• Use fan laws

Duct layout/design (18)

• Equal friction method• Supply or return systems• Balance the system

• Describe static regain method

• Compare them

Project

• Design problem• For example: Given cooling and heating load design

HVAC for the building

• Research problem• Analysis based problem. For example:

• Find the optimum solution for….• Developed control strategy for…• Life cycle cost analysis for …• ……….

Pumps and Fans

• Power law

• Types and basic properties

• Selection process

DOAS System

• www.doas.psu.edu

DOAS with multi-split systems

Fresh air?

DOAS fresh air configurations

DOAS fresh air configurations

Cooling and Heating Loads (For Project)

»Zone orientation

Commercial building

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

EconomizerEconomizer (fresh air volume flow rate control)

»mixing

»damper

»fresh

» air

»T & RH sensors

»recirc.

» air

»Controlled device is damper

» - Damper for the air

» - Valve for the liquids

Economizer – cooling regime

How to control the fresh air volume flow rate?

»% fresh air

»Minimum for

» ventilation

»100%

»If TOA < Tset-point → Supply more fresh air than the minimum required

»The question is how much?

»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.

»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 < Tset-point start closing the damper

» till you get T indoor air = T set-point

»

»Other variations are possible

Desiccant wheel

»Figure 3 – A desiccant-based cooling system combined with regenerative heat exchanger, vapor compression cooling, and evaporative

humidifier (hybrid system).