designing for human comfort and energy efficiency · designing for human comfort and energy...

DESIGNING FOR HUMAN COMFORT AND ENERGY

EFFICIENCY

CREATING A MORE COMFORTABLE AND PRODUCTIVE WORK ENVIRONMENT WORLD ENVIRONMENT AND LOWERING

OPERATING COSTS - YOU WILL TAKE WITH YOU A NEW WAY OF THINKING ABOUT YOUR BUILT ENVIRONMENT

A ONE HOUR COURSE BY:

Philip J. Bisesi, PE

and

David Purcell, BME, Acoustics

Michael Marion, BLA, Engineers Assistant

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Engineering Manual © 2007 Philip J. Bisesi, PE Affiliated Consultants, Engineers

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OPTIMIZING HUMAN COMFORT AND CONSERVING ENERGY

TABLE OF CONTENTS

� 1. INTRODUCTION �1.1 Introduction to Affiliated Consultants, Engineers �1.2 Introduction to this Book 1.3 Preface 1.4 Definition & Abbreviations 2. BASIC 2.1 Basic Concepts �2.2 Energy Systems and Human Comfort 2.3 Psychometrics � 3-9 10. SPECIFICATION �10.1 Start, Commission, and TAB Specifications �10.2 Retrocommissioning

Specifications 10.3 Equipment Guidelines 11. CHECKLISTS �11.1 Physical Plant Improvements �11.2 Inspection Report & Follow - Up � 12-19 20. DESIGN

20.1 Design Hints 21. DETAILS 21.1 Design Details to Facilitate TAB 21.2 Ducts 22. DUCTS 22.1 Ducts 22.2 Sizing for Balancing

22.3 Trane Ductulator 22.4 Trane Duct Leakage

Newsletter 23. PIPING 23.1 Piping 23.2 Sizing for Balancing 23.3 Flow Control 23.4 B&G System Sizer Slide Rule 23.5 Taco & B&G Slide Rules � 24 25. STANDARDS

25.1 ASHRAE Std. 111-1988 25.2 ASHRAE Handbook 1999 � 26-29 30. CASES �30.1 AC System Optimization Procedures �30.2 Energy Conservation Thru TAB � 30.3 Fan Operating Cost Optimization by Balancing AC Systems 30.4 Lee County Hospital Case History � 31-59 60. PERFORMANCE 60.1 Fan Performance 60.2 Pump Performance � 61-69 70. INSTRUMENTS 70.1 Instruments –Pictures 70.2 Applications � 71-74 75. MEASUREMENTS 75.1 Pitot Tupe Traversing 75.2 Air System Pressure

Measurements � 76-79 80. REPORTS 80.1 Tab Forms (Blank) 80.2 Typical Balancing Report 80.3 Exercises(Separate Cover) 80.4 Notes – Q & A 81-89 90. APPENDIX 90.1 Equations �� Bound in this book � Abridged in this book � On CD in this book � Hold for Future


1.1 Introduction to Affiliated Consultants, Engineers

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MISSION STATEMENT

Clients receive complete facilities engineering from feasibility studies through integrated design, with exact

calculations, reduced safety factors, TAB and commissioning. This comprehensive approach produces lower cost

construction, a more comfortable environment, on-time start-up and lower operating costs. Our basic philosophy is

to design, retrofit and test systems that we and the Owner can operate and maintain. We base renovation work

upon understanding the original design and improving upon it and not applying new hardware without first

optimizing the existing systems. We strive for maintainability, sustainability, and conservation of resources and

energy.

FIELDS OF PRACTICE

Air Conditioning and Heating Ventilation and Industrial Exhaust Industrial Hygiene Indoor Air Quality Electrical Lighting Boilers & Chillers Piping & Plumbing Controls & Instrumentation Process

Energy Conservation

Heat Reclamation

Air & Water Conservation

Utility Cost and Rate Analysis

Plant Facilities and Utilities

Noise & Vibration

Steam & Condensate

Fire Protection

Air & Water Pollution

Economics

SCOPE

Integrated Design ~ Studies: Feasibility, Operating, and Economic ~ Commissioning Project Supervision ~

Troubleshooting ~ Testing, Balancing, and Fine Tuning Systems Operating and Maintenance Manuals ~

Education & Training Start-up ~ HVAC Design & TAB education ~ Service and Performance Analysis

CLIENTS SERVED

Industries, Institutions, Government, Building Owners, Consulting Engineers, Architects, Interior Designers,

Mechanical & Electrical Contractors, and Design/Build Contractors.

1.1.1


1.1 Introduction to Affiliated Consultants, Engineers

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PHILOSOPHY

To design, renovate and test systems that we and the owner can operate, and achieve maintainability,

sustainability, and conservation of resources and energy.

When renovating, we study the original design and improve upon it and do not apply new hardware without first

optimizing the existing systems.

GENERAL PRINCIPLES

Follow the NSPE Code of Ethics for Engineers; the public safety, health and welfare are paramount. Everything

that we do is a professional service, not a commodity.

Professional Engineers are personally responsible for and seal all work. Duty to clients requires us to stay

abreast of basic theory and application through continuing education and professional development. Knowledge

and expertise is our stock in trade.

Provide unique solutions to each assignment, not copy past jobs. We do not make quick decisions based upon

what we are told, nor do we blindly follow directions without first studying and understanding the assignment,

then calculating, testing and following through from basic principles to optimized conclusions.

FOUNDATION

Philip J. Bisesi, PE, BSME worked for Government, Industry, and A/E firms as a senior ME/EE. He founded

Affiliated Consultants Engineers in 1974 to do PME design and physical plant improvements based upon energy

conservation studies. We concluded that retrocommissioning, including test, adjust and balance is the number

one energy conservation measure. Clients receive complete facilities engineering from feasibility studies through

integrated design, with exact calculations, reduced safety factors, TAB and commissioning. This comprehensive

approach produces lower cost construction, a more comfortable environment, on-time start-up and lower

operating costs.

PROFESSIONAL CERTIFICATIONS

PE, US Green Building Council LEED AP, aee Certified Energy Manager, Commissioning & TAB

1.1.2


2.2 Energy Systems and Human Comfort

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At Affiliated Consultant, Engineers our primary work is in existing buildings,

doing energy conservation work and making them more comfortable. Testing,

adjusting, balancing and commissioning buildings is an important part of our services.

I will concentrate on the envelope mechanical and electrical features of

buildings that make them comfortable and enhance human wellbeing. This also

applies to process work. The design engineer must understand these principles, as

must the commissioning engineer to assure optimum building performance.

Understanding comfort is the first platform upon which to set up a building

HVAC system. The body can acclimate to wide ranges of temperature, humidity, and

air velocity depending on the amount of clothing and level of activity. It is comfortable

if the heat lost out of the body is the same as the heat generated by the body.

David Purcell, ME, Acoustical Engineer will be presenting the noise,

vibration and acoustic concepts of human comfort.

2.2.1




First, we have sensible cooling. We transmit heat out of the body by

conduction due to temperature difference, by convection due to air currents traveling

across the body, and by skin radiating heat to surfaces around the body - or we gain

heat from radiation, such as from the sun.

Now take for example, that a person can be comfortable at 65˚ if the radiant

temperature of surfaces is high and drafts are minimal. This means that a cold

window with no heat under it is a problem. By the same token, if a south facing

window on a sunny day is hot, you can be very comfortable at 65˚ with warm radiation

on you. Furthermore, if a poorly designed window allows air to leak in, we are cold

from cold air on the floor regardless of what else we do.

When it is cold, we can help the situation by keeping the relative humidity up

at 50% so that our bodies do not evaporate excessive amounts of water. We can

also maintain comfort by wearing lightweight wool or some natural fibers (cotton) that

will allow the body to stay warm as compared to plastic fibers. So, we can be

comfortable at 65˚ if our space is well engineered.

2.2.3.1




Let’s look at the next extreme, a room at 80˚ in the summertime. How are

we going to be comfortable? We will dress lighter; move ample air across the body;

drop the relative humidity; and avoid the sun; we do not want a lot of radiant heat

coming into our bodies.

Let’s look at 75˚. How can a person be comfortable or uncomfortable in a

room at 75˚ and 50% relative humidity? Go into an office building where 60% of the

perimeter is glass and the sun is coming in on a summer day - just try to be

comfortable. The radiant effect at 75˚ is going to keep you uncomfortable no matter

what you do to air temperature. We have to use Venetian blinds or low emissivity

double pane glass. Airflow may be increased and temperature lowered to offset

radiant heat. Seventy-five degrees in the winter can be equally uncomfortable in that

60% glass building from that radiant effect.

To figure the effect of hot or cold radiant surfaces, just take the temperature

of that surface times its areas, the temperature of every other surface times its area,

divided by the total area. That gives you what we call the mean radiant temperature.

If that’s far above room temperature – or far below room temperature, you have

problems of heat and comfort. To combat it in the winter, we’ll put radiant heat under

the window. Combating it in the summer, if it is high, is rather hard. Your body or

any two bodies will radiate heat between themselves by a mathematical function of

their temperatures because a couple of other factors. The body is very susceptible to

this radiant heat. Ideally, if we could have 65˚ fresh air surrounding us, enough

radiating heat from the sun, and a nice slow air motion, say, out on a sunny day when

you are walking - there is no better sensation, is there? If you are in a room, where

it’s just a neutral room – for example, an inside room with no windows in it – you just

about have to maintain 75˚ to feel comfortable and warm.

So, I caution against glass more than 20%, because it is hard to handle and

has a high life cycle cost. I don’t encourage doing away with windows. It is

necessary for the eye to adjust itself and the senses to identify with the outdoors. We

can run studies that say nobody is bothered by working in a windowless room, but

these studies are flawed because they do not consider human nature. People do not

know why they are comfortable or uncomfortable; they just are.

2.2.3.2 2




Compare this with looking at a ceiling full of mechanical/electrical stuff that is

distracting. You are uncomfortable looking at this disorganized mess rather than

looking at some nice scenery, even if you don’t know why. I was an engineer for ten

years before an architect finally made me start dealing with the subconscious.

I can not thoroughly cover heating and cooling load calculations in this

course. Let me make you aware, though, that windows transmit so much heat, they

become a large portion of the load that gets factored into the mechanical equipment.

So much so, that you may need a lot of mechanical equipment to overcome their heat

gain. It may be uncomfortable just from a big draft in the room with all the air that is

flowing in to cool it because of all the windows. Venetian blinds are a big help

towards getting heat out. To give you a reference: 200 BTU a square foot – normal

amount of heat coming in a window. For shade from the exterior, we can get it down

to about 40 BTU a square foot by having a tree, an overhang – something like that –

north light by being on the north side of the building; or, we can have the same thing

by having a little overhang on another orientation. This is very comfortable – this

natural light doesn’t have much glare. The shading that we can provide inside a

room is much less effective. The sun comes through the glass, heats up somewhere

behind the shading material and also heats up the shading material (whatever it is)

and we get radiation into the room. Now, the shading material bounces something

back out, so we may get a factor of 50% and end up with 100 BTU a square foot

coming into the room. We can usually do something about the walls, especially with

insulation and light surfaces. High mass, well insulated walls delay the load and

average temperature, greatly improving mean radiant temperature and comfort.

Insulate roofs well. Back to the windows – if they leak, you can have as much heat

loss on a windy day through the leaks around windows as everything else put

together.

As far as a cooling load from people: you think of a room packed with

people as hot – it might be. But the BTU from people is generally not as great as the

other sources. People are a small proportion of the problem. Lights and equipment

are important.

2.2.3.3




We’ve talked of air motion, we’ve talked of air temperature and explained

how we can be comfortable at 65˚ or 80˚, but we haven’t talked enough about relative

humidity. With the typical air conditioning system there is not much control over

relative humidity. We will be in the range of 50% at full load unless we pack a whole

lot of people in the room or attempt to use large outdoor air quantities with face and

bypass or modulating coil control. Here is a problem that’s very hard to be

comfortable in. We’ll have to move more air in motion, keep the temperature up -

ideally, for a night club, we would like 80˚ and 30% relative humidity so people could

be warm and yet if they got very active and perspired, they could evaporate moisture

and cool themselves off.

People very lightly dressed, sitting, can be comfortable as well as people

more heavily dressed and active only if the relative humidity is low. This is the worst

design problem there actually is – to keep a couple comfortable – a woman lightly

dressed and a man in a suit – both dancing. When you get that relative humidity up

there at 80% by using inexpensive commercial air conditioning equipment, you try to

drive the room temperature down to 70˚ to say that you cool people and now you get

a cold, clammy effect. You can try to overcome it by changing temperature and it

doesn’t work to overcome the high relative humidity – you have to keep air motion up

and relative humidity down in order to be really comfortable.

The air’s carbon dioxide content and ozone content also effect comfort and

give a sense of stuffiness, which makes it feel hotter. Outdoor air control (OA) is an

important part of air conditioning. Accurate OA volume setting is required for TAB.

We talked about what keeps a person comfortable at many given

temperatures, so why do we set thermostats at exactly one temperature within plus or

minus one degree? With the energy crisis, we were told to drop thermostats to 65˚.

At Home Federal Savings & Loan we didn’t. We just turned the boiler off instead.

We’d get the building up to 75˚ first thing in the morning, shut the boiler off and then

let it free-wheel all day long. On a typical day, we were running when it was 65˚

outside with 50% relative humidity and lots of sun coming in the south window without

adding heat or refrigeration. On most winter days we were free-wheeling the building

without either heating or cooling, running the ventilation system and just taking the air

whichever way we could and we had some spaces in the building at 70˚ and some at

2.2.3.4




75˚. On extremely cold days, we ran the perimeter radiation to keep the mean radiant

temperature up.

I consider that a better energy saving method than trying to set the

thermostats at 65˚ and trying to maintain a level 65˚. Just shut off heating and air

conditioning and turn on the ventilation and circulate the building and free-wheel it.

One thing that helps and contributes to comfort when freewheeling is if you have

rooms without a lot of glass. If you can have rooms without big heating and cooling

loads, that don’t have big swings in effect from outside, then you can do more of this.

The boiler was off; the hot deck was on return air. The chiller was off; the cold deck

had evaporative cooling.

Human comfort can drive energy conservation work. Testing, adjusting and

balancing must be more than just setting dampers and valves. A devotion to

providing human comfort is the hallmark of a professional TAB engineer.

2.2.3.5

Engineering Manual © 2009 David Purcell, ME Quality Environments

2.2 Acoustical Design Guidelines

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Acoustical design in required in every space where humans live, use,

or traverse. Acoustical design is divided into two branches. The first is Noise

and Vibration Control. This branch is responsible for ensuring that all

mechanical and electrical systems meet reasonable noise levels. Most

buildings are done without any acoustical specifications being prepared. This

lack of specifications and design understanding means that most buildings

have noise problems.

The second branch is Architectural Acoustical Design. This branch is

responsible for each of the following:

1) Building Interior Noise - In order to allow the people inside

businesses or homes to function without disturbance, the design must

consider all sources of interior noise. This can include HVAC, other

machinery, talking, etc. The design must minimize or eliminate these sounds.

If they do not, the worker or person will require more time to get the job done.

This increased time means that the cost to perform the job will be raised.

There are two additional legislative requirements that require design

knowledge. These apply to multi-family construction as well as medical

information (HIPPA). In 2002, North Carolina passed legislation to insure that

multi-family noise concerns would be reduced. The legislative design

requirements have not been followed and contractors who install these

systems do not know how to install them properly. Federal HIPPA was

passed to protect patient information both electronically and audibly. This

requires that al examining rooms, billing areas, etc. are designed to contain

the sound within them to provide privacy. Both of these design problems can

lead to lawsuits if they are not acknowledged and properly designed.

Engineering Manual © 2009 David Purcell, ME Quality Environments

2.2 Acoustical Design Guidelines

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2) Building Exterior Noise - Exterior noise must be minimized to allow

people within a structure to work without interference. This is done by

ensuring that walls, windows and doors are designed to satisfactorily

attenuate the noise. It also requires that all other building penetrations be

treated. These are usually intakes or exhausts. Outside noise sources

usually include traffic, airplanes, trains, adjacent plants, parades, harsh trucks,

jack hammers, street sweepers, cooling towers, chillers, etc. It should be

noted that these are not all continuous noise sources.

3) Exterior Structure Noise - Exterior noise must be minimized to allow

outside or open structures to be used satisfactorily. These structures include

amphitheatres, bus stops, picnic areas, gardens, zoos, cemeteries etc. The

typical design will use a wall or barrier to minimize the external noise. This

design is also becoming popular with subdivisions that want to mitigate traffic

noise intrusions. The NC DOT is now using walls or berms to minimize noise

in housing areas that are along interstate highways. One should also consider

whether the land is acceptable for the exterior use planned.

The skill to plan, specify and design for not normally part of an

architectural or engineering firm's skill sets. This requires the help of

someone skilled in acoustics who can determine the needs, specify the

solutions and ensure that the designs are installed as specified.



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VISUAL COMFORT

Principles:

1. Eye responds to brightest item seen by closing pupil-opening size.

2. Eye responds to contrast and glare by losing acuity.

3. Eye sees better with 30 foot-candles average indirect lighting

(1 watt/square foot) than 100 foot-candles direct lighting

(4 watt/square foot).

4. Room surfaces should be light and not shiny.

5. Do not allow flicker, which is cause by voltage variations, and is

fatiguing. Do not mix motor receptacle and lighting on the same

circuits.

2.2.5




AIR QUALITY

Principles:

1. Supply filtered, clean, tempered air.

2. Vapors must be bellow threshold of nuisance, not only OSHA limits.

3. Pollutants have a cumulative effect.

4. No smoking.

5. All outdoor air must be adjusted to a suitable temperature, humidity,

and air cleanliness before introducing it to the room. Large quantities

require a pre-conditioning unit.

6. Pollution must be exhausted at the source. Allowing it into the general

air makes clean-up difficult. Dilution is not effective.

2.2.7




ACOUSTIC COMFORT

Principles:

1. We hear every sound in our surroundings.

2. We concentrate on the sounds in order of our need; however,

unwelcome background noises will distract us.

3. The brain cannot process two sounds simultaneously; one sound may

be masked by another. This extra sound may be processed

sequentially or it may interfere with the important sound.

4. It is important to minimize unwelcome noise so that we do not fatigue

or fail to fully understand what we should be thinking about.

5. Some can multitask simultaneously and some cannot effectively

multitask simultaneously.

6. Eliminate distractions from machine noise to improve productivity and

production quality.

2.2.9