ARE2014. Building Equipment and System DesignARE3078. Building Equipment Systems

HANYANG UNIVERSITY, ERICA CAMPUS

School of Architecture and Architectural Engineering

3rd year undergraduate

Prof. Kyoo Dong Song, Ph.D.

Tel: (031)400-5135

E-mail: kdsong@hanyang.ac.kr

http://aesl.hanyang.ac.kr

Reference Books and Resources

CHAPTER 1.

INTRODUCTION

1.1 Vernacular versus Modern Architecture

1.2 The Impact of Buildings on Global Environment

1.3 The Scope of Building M/E Systems

1.4 The Impact on Space Planning

1.5 The Impact on Architectural Design

1.6 The Impact on Construction Cost

1.7 The Impact on High-rise Building Design

1.8 Energy and Energy Conversion

1.9 Building Form and HVAC Load

1.1 Vernacular vs Modern Architecture

New York City, NY, U.S.A.

A House in Nepal

The term vernacular is derived from the Latin vernaculus, meaning "domestic, native, indigenous"; from verna, meaning "native slave" or "home-born slave".

Vernacular architecture is a term used to categorize methods of construction which use locally available resources and traditions to address local needs and circumstances. Vernacular architecture tends to evolve over time to reflect the environmental, cultural and historicalcontext in which it exists. It has often been dismissed as crude and unrefined, but also has proponents who highlight its importance in current design.

1.1.1 Vernacular Architecture

A House in Korea

• Modern buildings are no longer just shelters from rain, wind, snow, sun, or other harsh conditions of

nature. Rather, they are built to create better, more consistent, more productive environments in which

to work and to live.

• Modern buildings mostly depend on the mechanical and electrical systems for heating, cooling and ventilation.

• Modern buildings consume more water than before.

John Hancock Center, Chicago, IL, U.S.A.

1.1.2 Modern Buildings

• More than 60% of energy is consumed for HEATING, COOLING, VENTILATION

and LIGHTING systems in commercial buildings.

1.2 The Impact of Buildings on Global Environment

Ozone depletion Resource depletion (energy and material) Environmental pollution Global warming

1.2.1 All Pollutants Produced From Energy Conversion (Combustion)

The amount of each air pollutant can easily be calculated by the chemical content of a fuel.

1.2.2 Example

- A large office building with 55,742㎡ gross floor area.- Average electric power demand for heating, air conditioning, lighting , plumbing, fire protection, elevator,

and other equipment is 86W/ ㎡.- Building operates about 4000 hours a year.

- The annual electric energy consumed:

55742 ㎡ⅹ 4000 hr/yr ⅹ 86W/ ㎡≒ 19,200,000kWh/yr

- Assuming that the utility’s power-generating plants is coal-fired

Carbon dioxide(CO2): 19,200,000 ⅹ 1090g = 20,928,000kg/yrSulfur dioxide (SO2): 19,200,000 ⅹ 9.0g = 172,800kg/yrOxides of nitrogen(NOx): 19,200,000 ⅹ 4.4g = 84,480kg/yr

If a 10% energy conservation can be achieved through better design and controls for this building then the CO2 emission alone will be reduced by 2,092,800kg/yr

The complexity of M/E systems varies with:

• living standards of the society

• climatic conditions of the region

• occupancy and quality of the building

Categories of Building M/E systems:

• Mechanical system

• Electrical system

• Building Operation Systems

1.3 The Scope of Building M/E Systems

Mechanical Systems

HVAC: Heating, ventilating, and air-conditioning Site utilities: Water supply, storm-water drainage, sanitary disposal, gas supply Plumbing: Water distribution, water treatment, sanitary facilities Fire protection: Water supply, standpipe, fire and smoke detection, automatic

sprinklers, annunciation

Electrical Systems

Electrical power: Normal, standby, and emergency power supply and distribution Lighting: Interior, exterior, and emergency lighting Auxiliary: Telephone, signal, data, audio/video, sound, fire alarm, security systems

Building Operation Systems

Transportation: Elevators, escalators, moving walk-ways Processing: Production, food service Automation: Environmental controls, management

1.4 The Impact on Space Planning

The floor area for M/E systems depends on the occupancy, climatic conditions, living standards, and quality and general architectural design of the building.

The M/E space affects the gross floor area, footprint(the size and shape of the building’s ground floor), floor-to-floor height, geometry, and architectural expression.

Space planning for M/E systems is one of the most challenging and least developed procedures in the architectural design process.

Central equipment used for large buildings is usually bulky and tall, requiring floor-to-floor heights of 1.5 to 2 times the normal height

The duct work, lighting, and wiring of a commercial building usually require between 60 – 90 cm of ceiling cavity.

1.5.1 Early Building Forms

Prior to the development of reliable and affordable M/E systems, buildings designed for human occupancy followed a simple rule: every room must have exterior operable windows for daylight and natural ventilation.

Most buildings: L-, U-, or H-shaped, having either single or double-loaded corridors

Deep block-type buildings: open interior court for access to daylight and outside air.

1.5 The Impact on Architectural Design

1.5.2 Building Height versus Space Utilization

Buildings may be classified as low-rise, high-rise, and a number of other categories.

▪ Low-rise building

less than 7 stories or lower than 75ft(3.5m) from street level

reached by conventional fire-truck ladders

modern firefighting equipment, that definition is no longer valid, but still used by most building codes as the basis for classifying buildings

▪ High-rise building: buildings from 7 to 29 stories

▪ Super high-rise building: 30 to 50 stories

▪ Skyscraper: 51 stories upward

▪As the height of the building increases, more floor space is required for stairs, structural elements, elevators, lobbies, M/E system shafts, etc., causing reduction in the net usable space on the floor

Source: Mechanical and Electrical Equipment for Buildings, 10th Ed., p.380

1.5.3 Building Efficiency Factors

Factors used to evaluate the effectiveness of the building design:

Net-to-gross ratio (NGR)

Floor-efficiency ratio (FER)

1) Net-to-Gross Ratio(NGR)

GFANFANGR /100

NFA is the floor area that can be used by the occupants, excluding the area taken by stairs, circulation space, elevators, lobbies, structural columns, M/E equipment and shafts.

The NGR usually ranges from 60 to 90 percent. The NGR of highly technical buildings, such as research laboratories, computer centers, and hospitals may even be below 50 percent.

The objective in space planning is to improve the NGR while maintaining a proper balance between occupant’s comfort and productivity, M/E system performance, and initial and operating costs.

Where NFA= net floor area, [m2]

GFA=gross floor area [m2]

2) Floor-Efficiency Ratio(FER)

FER is used for office buildings to calculate the rentable space on typical rental floors.

)/(100 GFANRAFER

Normally, an FER of 85% is considered an excellent design.

where, NRA=net rentable area[m2]

GFA= Gross floor area [m2]

1.5.4 Geometric Factors

Factors used to evaluate economics and energy-effectiveness relative to building geometry and form:

VSR: volume-to-surface ratio

APR: area-to-perimeter ratio

1) Volume-to-Surface Ratio

VSR = V / S

where, V=volume of building[m3] S=total exterior surface of building[m2]

To be cost-effective and energy efficient, the building geometry should minimize exterior surfaces (walls and roof) and maximize interior volume (floor area x height).

Any building with height greater than half its base dimension is less energy efficient and more costly to build than on with height less than or equal to half its base dimension.

The VSR can also be used to evaluate the optimum size of buildings by comparing smaller numbers of large buildings and larger numbers of small buildings. The answer is in favor of the larger buildings.

The optimum VSR of a building is either a semispherical dome with diminishing upper floor areas or a semicubical building with equal floor areas and height half its base dimension.

2) Area-to-Perimeter Ratio(APR)

The APR is related to aspect ratio(AR) of the building, defined as the length(longer dimension) divided by the width of the building.

APR is the typical floor area divided by the perimeter length of the floor

(most upper floors are substantially the same)

PAAPR /

The larger the APR, the higher the energy efficiency

A round or square building should have the optimum APR

Where, A= typical or representative floor area of building [m2]

P=linear dimension of perimeter of a typical or representative floor [m]

Fig. 1-9 Comparison of the APR values of several geometric configurations.

A rectangular building with

maximum daylight and minimum

solar heat gain in the cooling

season could override the APR

factors.

The final design will depend on a

computer simulation of the HVAC

and lighting load on an hour-by-

hour basis.

1.5.5 Impact on Building Exterior Design

The Major influence of M/E systems on modern architecture has been not only in building height but in architectural style, façade, form, and expression.

Pompidou Center, Paris, France

Designed by Renzo Piano and Richard Rogers

Opened on January 31, 1977

Most modern buildings are influenced by the presence of M/E systems, as evidenced by the following architectural design styles:

Penthouse design

Flattop design

Intermediate floor bands design

Signature design

Sears Tower, Chicago, IL, U.S.A. Pierre Laclede Center, St. Louis U.S.A.

MetLife Building (59 stories), New York, NY, U.S.A.

(Originally Pan Am Building)

Penthouse design:

designed to enclose the elevator equipment and elevator overtravel, cooling towers, exhaust fans, and other equipment

Flattop design:

designed to house central M/E equipment and to conceal upper-level M/E equipment (cooling tower, air-handling units, and elevator equipment)

Intermediate floor bands design:

High-rise buildings of over 30 stories are usually designed with one or more intermediate floors to house central M/E equipment.

Signature design:

Postmodern design in the 1990s for individuality and sculpture-type rooftops. Cooling towers must be concealed by locating at or near the ground level or may be concealed within the building.

1.6 The Impact on Construction Cost

1.6.1 Impact of Building Height on Construction Cost

A taller building requires more time and hoisting equipment and complicated scheduling to raise the material to the upper floors

For a building taller than 10 stories, the unit cost per floor area increase about 5 to 15% for the next 5 stories and another 10 to 15% for each additional 5 floors.

For example, if the unit cost for a 10-story building is $150/ft2, then the cost for a 25-story building, using 10 percent as the incremental cost, can be estimated as follows:

Average unit cost=[($150 x 10)+(165 x 5)+(182 x 5)+($200 x 5)] / 25 = $173/ft2

1.6.2 Impact of M/E Systems on Construction Cost

The impact of M/E systems on construction cost varies depending on:

the type of building

standard of living

architectural design

M/E systems selected

1.6.3 Impact on Operating Costs

The operating cost includes the cost of routine maintenance, repairs, replacements, and utilities.

Most architectural and structural components of a building(except for roof) are normally long-lasting and do not need frequent replacement.

Most M/E systems not only consume energy but also require ongoing maintenance and repair.

Over a life cycle, the cost of owning and operating M/E systems may outweigh the initial capital investment of the entire building.

Therefore, efficient M/E systems and management are very important.

1.7 The Impact on High-rise Building Design

In high-rise building design, there is no single solution to a problem.

Two buildings of similar size and configuration located on different sites may favor different M/E systems and central plant location, depending upon climate and the economic and cultural background of a country.

▪ M/E system takes considerable space- The average M/E floor space in an office building

is about 4% of the total building gross floor area

e.g. 1) for 25stories, 500,000 ft2 (46,45 1m2) gross floor area, 20,000 ft2 (1,858 m2) should be initially allocated as M/E equipment space.

e.g. 2) Two floors are needed for M/E equipment in a 50-story building, and four floors in a 100-story

building.

▪ Optimum solutions are a result of close coordination between the architect and the M/E engineers.

1.7.1 Factors affecting the location of a central plant

Accessibility for loading/ unloading equipment

Proximity to the outside air supply and exhaust air discharge

Adequacy of floor height

Interference with a convenient parking plan

Safety. equipment such as boilers, chillers, and liquid-filled transformers should be confined within fireproof walls.

Proximity of system components, such as the chiller and the condenser, and the cooling towers.

Ease of maintenance.

Vibration and noise from equipment

Aesthetics

Source: Mechanical and Electrical Equipment for Buildings, 10th Ed., p.372

Reasons favoring upper or lower central plant locations

1.8 Energy and Energy Conversion

1.8.1 Common Energy Sources

• All buildings require electrical power.• HVAC systems also require fuel for heating and cooling.

1.8.2 Efficiency of Energy Conversion Processes

• Energy exists in the form of heat, light, chemical, sound, mechanical, and nuclear energy.

• Energy can be neither created nor destroyed but can be converted from on form to another.

• Energy conversion is never 100% efficient.

• The loss is usually in the form of low-level(temperature) heat, which is not readily useful.

1) Common Energy Sources and Conversion Efficiencies

2) Energy Conversion Efficiencies of the Heating Process

3) Electric Heat Pump (EHP)

• The electric heat pump utilizes electrical energy to “transport” heat energy from the building exterior to the building interior

• The process is not an energy conversion process but rather a transfer process

1.9 Building Form and HVAC Load

• Internal Load Dominated (ILD) Buildings

Thicker and taller buildings have more floor space away from climate influences; being electrically lit rather than daylit, they generate heat and need cooling all year.

• Skin Load Dominated (SLD) Buildings

Thin buildings, in which nearly all spaces have an exterior wall, need heating in cold weather and cooling in hot weather; electric lights by day are largely unnecessary.

Mechanical and Electrical Equipment for Buildings 10th Ed., John Wiley & Sons Inc., p.213

1) Internal-Load-Dominated Buildings

• These buildings typically have energy-use patterns dominated by heat gains from lighting, equipment, and people and have limited opportunities for the use of on-site or natural energy sources.

Mechanical and Electrical Equipment for Buildings 10th Ed., John Wiley & Sons Inc., p.213

Internal-Load-Dominated Buildings – Continued

Zoning of Internal-Load-Dominated Buildings

• Perimeter zones (within 10m from windows):

• At least four zones according to the window orientations.

• These zones are mostly affected by the outdoor conditions, such as air temperature and solar radiation.

• Require heating in winter and cooling in summer.

• Interior zone:

• This zone is mostly affected by the heat generated by the lighting fixtures, office equipment and people.

• May require cooling all year.

Mechanical and Electrical Equipment for Buildings 10th Ed., John Wiley & Sons Inc., p.214

2) Skin-Load-Dominated Buildings

• These buildings typically have energy-use patterns dominated by heat gains and losses through the building envelope with opportunities for the use of on-site or natural energy source.