Welcome to the

2013 Energy Efficiency Expo!

Thank you to our session sponsors!

Elara EngineeringDon McLauchlan, P.E.

Dustin Langille

2

2013 Energy Efficiency ExpoSeptember 10th, 2013

Unlock Energy Savings with

Heat Recovery

Presentation Outline

•Introduction

•Principles of Heat Recovery

•Types of Heat Recovery

•Case Studies

•Questions

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Elara Team

Don McLauchlan, Principal, P.E., C.E.M., LEED AP

−BSME

−Mechanical design engineer

−Mechanical design/build contractor

−Over 35 years in the industry

−Principle engineer on 12 LEED certified projects (4 Gold)

Dustin Langille, Senior Engineer

−MSME

−Mechanical design engineer

−Over 5 years in the industry

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Principles of Heat Recovery

The US DOE estimates that between 5 and 12 quadrillion BTU/year

is lost to waste heat1

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

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Hydroelectric

Power

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1US DOE: Waste Heat Recovery: Technology and Opportunities in U.S. Industry, March 2008

Principles of Heat Recovery

•General HX Equation: Q= ΔT(lmt) x U x A

•Terms:

•Approach temperature (T (hot in) – T (cold out)

•Turbulent/Transition/Laminar Flow (Reynold’s Number)

•Fouling Factor

•Log mean Temperature difference = (Ta – Tb)/ln( Ta/Tb)

•Counter Flow vs Parallel Flow

•Effectiveness

•Energy Balance

•Energy Penalty

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Principles of Heat Recovery

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Principles of Heat Recovery

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Principles of Heat Recovery

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Principles of Heat Recovery

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Principles of Heat Recovery

•Sources of “waste” heat:

−Building exhaust

−Boiler exhaust

−Process heat

−Simultaneous heating and cooling

−Heat rejected from AC/refrigeration equipment

•Recovered energy reduces heating and cooling loads

−Significant ongoing energy and money savings

•Also can reduce initial system size and costs

−Boilers

−Chillers

−Piping

−Pumps

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Example Types of Building Exhaust Heat Recovery

•Energy Recovery Wheels

•Plate and Membrane Heat Exchangers

•Run-around Coils

•Heat Pipe

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Energy Recovery Wheels

•A heat absorbing wheel that slowly

rotates between supply and exhaust air

streams

•Recovers sensible and latent energy

•Effective in summer operation and

dehumidification strategies

Datacenterknowledge.com

Cold OA

Warm

Exhaust

Picture: Datacenterknowledge.com

Cold OA

Warm

Exhaust

Winter Conditions

To Building

To Outside

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Energy Recovery Wheels

Advantages•Sensible and latent heat recovery

•High effectiveness

Disadvantages•Cannot be used where total separation of

exhaust and supply is required

•Wheel is susceptible to damage and

degradation

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Lessons Learned

◊ Questions

Picture: Ecobuildingpulse.com

Plate and Membrane Heat Exchanger

•Series of parallel plates providing heat transfer between exhaust and

supply air

•Generally only provide sensible heat transfer

−Plastic and paper systems allow for latent energy recovery as well

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Lessons Learned

◊ Questions

Picture: Water-foods.com

Plate and Membrane Heat Exchanger

Advantages•Can be used with contaminated air

•Potential for latent heat transfer

•Lower air-side pressure drop than energy recovery wheels

•Passive system (no moving parts)

Disadvantages•Physically large

•Less effective than energy recovery wheels

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Run-around Coils

•Piping loop between exhaust and

supply

•Requires installation of coils in

both exhaust and supply

ducts/plenums

•Water/glycol mixture

•Recovers sensible energy only

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Run-around Coils

Advantages•More cost effective when exhaust and supply are separated

by large distances

•System design flexibility for multiple exhaust/supply streams

•Flexibility of seasonally changing modes of operation

•System life and maintainability

•Up to 50% effective with careful coil and pump selections

Disadvantages•Circulation pump uses energy

•Typically no latent heat transfer

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Run-around Coils

Design Comments

•Critical coil selections

•Variable speed pumping

•Controls

•Freeze protection

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

3 Coil Run-around

•Run-around coil providing

pre-cooling and reheating for

dehumidification

•Pre-cool coil can double as

heat recovery coil

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Reheat

Coil

Main

Cooling

Coil

Precool

Coil

Heat Pipe

•Piping loop between exhaust and supply similar to run-around coil using

refrigerant instead of water

•Refrigerant vaporizes in one coil, gathering heat energy, and releases

energy in the supply coil when it condenses

•Pressure within loop can be adjusted to properly facilitate phase change

•Recovers sensible heat only

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Case Study: Park Alexandria

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Desuperheater heat recovery for

domestic hot water heating

•Heat exchanger on chiller recovers

heat from hot refrigerant gas

•Preheat tanks store hot water

•Nearly entire summer DHW load met

•Improved chiller efficiency via lower

head pressure

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Implementation Cost: $90,000

Estimated Annual Savings: $26,000

Simple Payback: 3.5 Years

Pre

heat Tank T

em

pera

ture

•Exhaust air run-around recovering

approximately 40% of the exhaust heat

energy

•Significantly reduce the energy consumed

by the existing makeup air units

Implementation Cost: $183,200

Annual Savings: $127,010

Simple Payback: 1.44 Years

Case Study: Heritage at Millennium Park

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Heat recovery wheel with bypass and return air

path for additional humidity control

Case Study: Data Center Heat Recovery

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

•Campus data

center will provide

100% of building

heating needs

with use of water-

to-water heat

pump

Main Air Handlers -

Heating Mode

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Case Study: Loyola Information Commons

•Combined three coil

run-around and

exhaust heat

recovery

•Variable speed

pump for optimized

heat recovery

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Main Air Handlers -

Cooling Mode •Summer mode

provides

dehumidification for

radiant slabs

QUESTIONS?

◊ Introduction

◊ Principles

◊ Types

◊ Case Studies

◊ Questions

Thank you for joining us today.

Conference presentations can be found online: https://www.etouches.com/ehome/57796/105257/

You will receive a survey and link to all conference materials following the conference. We look forward to hearing your valued feedback!