BUILDING ENERGY EFFICIENT SCHOOLS

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					                                                                                                                ESL-HH-85-09-16




                                                BUILDING ENERGY EFFICIENT SCHOOLS

              James D. McClure, P.E.                                                    James M. Estes, P.E.
               Consulting Engineer                                                      Consulting Engineer
         Estes, McClure & Associates Inc.                                         Estes. McClure & Associates, Inc.
                   Tyler, Texas                                                             Tyler. Texas

   ABSTRACT                                                                officials and maintenance director meet with the
                                                                           mechanical and electrical engineers?
        Many new school buildings consume only half the
   energy required by similar efficient structures de-                  EDUCATIONAL PROGRAMMING
   signed without energy performance as a design crit-
   erion. These are comfortable and efficient while                         Educational programming is critical. Without
   construction costs remain about the same as those -                  a clear definition of needs and functions from the
   for extremely inefficient buildings. To accomplish                   school officials (number of students, curriculum,
   this, the school administrator must be an active                     methods, educational philosophy, etc.), the arch-
   participant in the design process. Energy efficient                  itect will have to make certain assumptions that
   school design is a team effort involving the arch-                   could ultimately affect how efficiently the new
   itect, engineer, and school administrator. This                      building is used. Needs should be evaluated and
   paper presents concepts and approaches to guide new                  defined for the present, immediate future, and life
   school projects for energy efficiency. Comments or                   of the building.
   approaches for energy efficiency in mechanical and
   electrical systems are included.                                     ARCHITECTURAL PROGRAMMING

   THE PROCESS                                                               Architectural programming follows educational
                                                                        programming and includes defining areas and rela-
        Building energy efficient schools is a process                  tionsh*ps of various spaces, budget restrictions.
   involving many steps. Successful programs utilize                    and design criteria. Almost every decision made
   the skills of many disciplines. Each decision made                   affects the energy efficeincy and consumption.
   in the process should consider the influence of the                  During this phase, school officials have the 1
   specific action on building energy performance and                                                                  o
                                                                        opportunity to set attitudes and requirements :r
   maihtenance costs, just as safety and functional                     energy performance. The school officials should
   aspects are evaluated. Figure 1 illustrates the                      be concerned about energy performance rather than
   variety of people involved at each event and typical                 specific design features.
                                                                                                                                  I
   time spans.
                                                                        SCAEMATIC AND DESIGN DEVELOPMENT

                                                                            The architect will develop schematics of the
        Selection of the architect and engineer (A/E)                  building after the architectural program is com-
   is one of the most important decisions the owner                    pleted. Several configurations and approaches may
   or school officials will make concerning energy                     be developed. This is the stage at which the mech-
   efficiency. Although the architect usually has the                  anical and electrical engineers should provide in-
   design contract with the school district, the success               put. When the various schematics are evaluated
   of a project and its energy performance depends on                  and estimated for cost, they should also be analyzed
   the entire design team, which includes the mechanical               for energy efficiency. The architect and engineer
   and electrical consulting engineers. Technical and                  working together at this preliminary and schematic
   professional qualifications should be the primary                   stage can more effectively investigate various HVAC
   criteria in selecting the design team. When select-                 and lighting options. Involving the engineer at this
   ing an architect to design a new school, school offi-               stage permits creativity and consideration of more
   cials should include the following type of questions                options. The approaches chosen can be integrated
   in their interviews:                                                                      the
                                                                       more effi~iently~into architectal design of the
                                                                                                                      I
                                                                       building.
   , Who are the members of the design team?
   . Who is the project architect? Who is the project
     mechanical engineer?
                                                                            After approval for the school district of one
                                                                       of the schematic approaches, the architect prepares
   , What specific energy efficiency features have                     design development documents that consist of draw-
     you incorporated in recent school projects?                       ings and outline specifications. At this point.
   . What schools have you designed? Who was the
     superintendent? Who was responsible for energy
                                                                       structural, mechanical, and electrical systems are
                                                                       defined. Review by the school district should in-
     efficiency?                                                       clude evaluation of size, orientation, space layout;
   . What type of economic analysis will be accom-                     educational suitability, quality, maintainability.
                                                                       and energy performance. Attention should be paid
     plished? Will trade-studies of energy efficient
     features be made?                                                 to zoning of air-conditioning systems, type of
   , At what point in the design process will the school               lighting systems, use of daylighting, control
                                                                       concept of air-conditioning, and complexity of




Proceedings of the Second Symposium on Improving Building Systems in Hot and Humid Climates, College Station, TX, September 24-26, 1985
                                                                                                                ESL-HH-85-09-16

   systems in comparison to resident and local mainten-                      Shape and size are architectural features that
   ance skills. Major changes beyond this point may                     may affect energy performance. A minimum surface to
   tesult in extra cost so school officials should                      volume ratio allows for the least amount of heat loss
   take time to carefully review the plans.                             or gain from the building envelope. Therefore, de-
                                                                        signs which result in increased surface area may
   DEVELOPMENT OF WORKING DRAWINGS                                      result in increased energy consumption. This, how-
                                                                        ever, must first be evaluated in view of designs
        Development of working drawings involve pre- -                  that may have more surface area but take advantage
   paring larger scale plans, locating equipment, and                   of daylighting and natural ventilation.
   working out details. School officials need to review
   these drawings at an intermediate stage for func-                    ENERGY PERFORMANCE AS DESIGN CRITERIA
   tional adequacy convenience, safety, and for in-
   corporation of energy conservation features.                              Energy performance of school buildings is best
                                                                        determined or defined in terms of the annual energy
   FINAL PLANS AND SPECIFICATIONS                                       consumption divided by the area of the building.
                                                                        Figure 2 shows a wide range of energy performance
        This phase of the work requires very little of                  for school buildings. These site value data were
   the school officials if early communication has                      obtained from energy studies of existing typical
   been thorough and successful. The design team                        Texas public schools. All schools observed had
   which includes the owner, architect, and engineer                    greater energy consumption than the Department of
   should review the plans and specifications to                        Energy's original proposed standards for areas with
   assure that all program requirements have been                       climates similar to Texas. The wide variations in
   incorporated. A thorough review before release                       energy performance illustrated in Figure 2 are the                '
   of the documents may avoid costly orders and delays                  result of several factors including building design.
   during construction.                                                 mechanical and electrical design, and operating
                                                                        techniaues. A desirable goal for new construction
   ENERGY EFFICIENT ARCHITECTURE                                        would be substantially better energy performance than
                                                                        the average in this sampling.
        When considering architectural aspects for
   energy efficiency in new school construction, sev-                   ENERGY EFFICIENCY IN MECHANICAL AND ELECTRICAL
   eral logical questions are evident:                                  SYSTEM

   .   How can the building be designed and oriented to                      Energy efficient mechanical and electrical
       rely less on mechanical and electrical systems?                  system design requires careful analysis of the ed-
   .   How can internal loads be reduced?                               ucation program. This is one of the first of the
   .   What new technologies and techniques are avail-                  engineer's design task. Correlating the educational
       able to reduce energy consumption?                               program needs to building use schedule and control
   .   What are the best cost effective design strategies               arecritical for energy efficient operation. HVAC
       for minimizing losses through the building                       systems and lighting systems must be flexible enough
       envelope?                                                        to provide heating, cooling, or lighting only to
                                                                        those spaces actually being used, if energy dollars
        In hot climates, lighting and air-conditioning                  are not to be wasted.
   account for more than half of the energy used in the
   average school. Therefore, the greatest architect-                        In conducting energy studies of more than 200
   ural opportunities for achieving energy savings lie                  school buildings, and designing mechanical and
   in designs that allow efficient and minimal use of                   electrical systems for more than 45 Texas school
   mechanical and electrical systems. Examples include                  districts, we have observed, evaluated, and designed
   daylighting, natural ventilation, passive solar                      numerous types of HVAC systems. These schools and
   energy, and etficient insulation. The building en-                   systems have a wide variation in energy performance.
   velope is an architectural feature directly related
   to energy performance and first cost. In hot                                Why would one elementary school have an energy
   climates, high solar load on the roof requires more                   consumption of 4.9 times and cost of 2.4 times of
   attention to roof insulation and design than to                       another school of similar design, use, size, and
   the walls. Strategic use of windows and manage-                       location (129,458 BTUH/sq. ft-vs. 26.000 BTUH/sq.
   ment of solar gain are required.                                      ft.)?

        Site selection of schools should include input                       The energy inefficient school had a central
   from the architect and engineer before the land is                   HVAC system employing absorption refrigeration
   purchased. Site factors affecting energy usage in-                   system, multizone air handlers, and no automatic
   clude terrain, wind, and orientation. Another                        controls to turn equipment on and off. The eff-
   site factbr affecting first cost and energy usage is                 icient school had individual units for each zone and
   utilities. These also should be investigated before                  incorporated a simple control system to schedule
   the site is purchased. For example, a site requiring                 on/off operations. This example represents an ex--
   a sewage treatment plant and/or lift station results                 treme case. We have however, observed that schools
   in additional first cost, energy costs, and main-                    with central type systems and large multizone sys-
   tenance costs.                                                       tems consistently have a higher energy consumption
                                                                        than schools with multi-unit non-central designs.




Proceedings of the Second Symposium on Improving Building Systems in Hot and Humid Climates, College Station, TX, September 24-26, 1985
                                                                                                                                                             ESL-HH-85-09-16


      HVAC SYSTEMS                                                                                includes the following:

                The t y p e of s c h o o l b u i l d i n g , u s a g e , and fun-                  .
                                                                                                   .
                                                                                                        U s e of d a y l i g h t i n g
                                                                                                        P r o v i d e h i g h p r e s s u r e sodium l i g h t f i x t u r e s c s n r
      c t i o n s w i l l have a g r e a t i n f l u e n c e on t h e t y p e of
      system o r l i m i t t h e c h o i c e s t h a t w i l l b e b e s t f o r                        outdoor l i g h t i n g
      a s p e c i f i c b u i l d i n g . For example, a b u i l d i n g l o c a t e d             ..   P r o v i d e m e t a l h a l i d e l i g h t f i x t u r e s f o r gymnasiums
      i n a h o t c l i m a t e , w i t h s t r a t e g i c a l l y p l a c e d and                .    I n s t a l l energy e f f i c i e n t (reduced wattage) f l u o r -
                                                                                                        e s c e n t l i g h t i n g s y s t e m i n c l a s s r o o m s and o f f i c e s
      l i m i t e d g l a s s , and a d e q u a t e i n s u l a t i o n w i l l have
      a s m a l l s p a c e h e a t i n g l o a d . T h e r e f o r e payback                     .
                                                                                                  .
                                                                                                        Provide f l e x i b l e l i g h t s w i t c h i n g arrangements
                                                                                                        Utilize task lighting
      analysis i n t h i s case usually r e s u l t s i n the decision
      t o p r o v i d e a low c o s t h e a t i n g s y s t e m s i n c e t h e h e a t -         .     Follow recommended l i g h t i n g l e v e l s
      i n g l o a d i s s m a l l . I n f a c t , t h e r e may be o n l y a
      "warm-up" l o a d r a t h e r t h a n a " h e a t i n g load".              In                        The s c h o o l o f f i c i a l s s h o u l d p r o v i d e i n p u t t o
      a r e a s w i t h l a r g e f r e s h a i r and h e a t i n g l o a d s ( e g .             t h e d e s i g n team o n t h e F l e x i b i l i t y o f l i g h t i n g
      gymnasium, e t c . ) , a c e n t r a l n a t u r a l g a s f i r e d b o i l e r            which - p e r m i t s some l i g h t s t o b e t u r n e d o f f d u r i n g
,     with hot water c o i l s i n a air-handler a r e usually                                    a s i g n i f i c a n t number of s c h o o l h o u r s . For example,
      cost effective.                                                                             we have o b s e r v e d l i g h t l e v e l s o f 300 f o o t c a n d l e s
                                                                                                  n e a r windows i n a c a f e t o r i u m . The e n t i r e row of
      FIRST COST. ENERGY COST, AND MAINTENANCE SKILLS                                             f i x t u r e s n e a r t h e windows c o u l d h a v e been t u r n e d o f f
                                                                                                  w i t h o u t any a p p r e c i a b l e change i n l i g h t l e v e l . O t h e r
                Firsr: c o s t , e n e r g y c o s t , and m a i n t e n a n c e s k i l l        examples a r e t u r n i n g o f f some l i g h t s d u r i n g c l e a n i n g .
     r e q u i r e m e n t s a r e of primary c o n c e r n t o t h e s c h o o l
     d i s t r i c t . These a r e i l l u s t r a t e d i n F i g u r e s 3 . 4 ,                EXAMPLES
     and 5. These d a t a a r e based on t h e a u t h o r s ' ex-
     p e r i e n c e and o b s e r v a t i o n s i n t y p i c a l modern Texas                   ENERGY EFFICIENT ELEMENTARY SCHOOL                          - WHITEHOUSE          ISD
     s c h o o l s . The e n e r g y c o s t o f - a n y HVAC s y s t e m i s
     i n f l u e n c e d by t h e b u i l d i n g s t r u c t c l r e , c o n t r o l s ,                   I n 1979. Whitehouse I.S.D. c o n s t r u c t e d a new
     and u t i l i t y r a t e s . T h e r e f o r e t h e r e l a t i v e r a n k i n g s        Elementary School w i t h e n e r g y e f f i c i e n c y and main-
     may change s l i g h t l y f o r v a r i o u s n r o j e c t s . R e l a t i v e             t a i n a b i l i t y a s a r e q u i r e m e n t . During t h e 1983-84
     f i r s t c o s t r a n k i n g shown may v p r y depending o n                              s c h o o l y e a r , e n e r g y c o s t s were a p p r o x i m a t e l y f o r t y
     f a c t o r s such a s building s i z e , shape, l o c a t i o n .                           c e n t s p e r s q u a r e f o o t and e n e r g y performance was
     and d e s i g n .                                                                            a p p r o x i m a t e l y 26,000 BTU's p e r s q u a r e f o o t ( s i t e
                                                                                                  v a l u e s ) . The s c h o o l b o a r d , s u p e r i n t e n d e n t , s e l e c t e d
          The f o l l o w i n g a r e c o n c l u s i o n s t h a t t h e a u t h o r             s c h o o l s t a f f members, a r c h i t e c t , and t h e c o n s u l t i n g
                                                                                                  e n g i n e e r work t o g e t h e r a s a team t o d e v e l o p a n
     have d e r i v e d from a n a l y z i n g , d e s i g n i n g , and o b s e r -
                                                                                                  e n e r g y e f f i c i e n t s c h o o l t h a t would meet t h e n e e d s o f
     ving mechanical systems i n p u b l i c schools.
                                                                                                  Whitehouse I.S.D.                 Energy e f f i c i e n t f e a t u r e s i n c o r -
      .   I n d i v i d u a l zone t y p e u n i t s r a t h e r t h a n c e n t r a l
                                                                                                  porated i n t h e building include t h e following:
          o r m u l t i z o n e s y s t e m s c o s t less t o p u r c h a s e
                                                                                                        U t i l i z a t i o n of s p a c e is e f f i c i e n t . A l l s p a c e is
          and i n s t a l l .
      .   Energy o p e r a t i n g c o s t s of i n d i v i d u a l zone
                                                                                                        f u n c t i o n a l and some s e r v e m u l t i p l e p u r p o s e s .
                                                                                                        The HVAC s y s t e m i s h i g h e f f i c i e n c y s p l i t s v s t m
          s p l i t - s y s t e m e l e c t r i c d i r e c t e x p a n s i o n (DX) t y p e
                                                                                                        h e a t pumps. Each c l a s s r o o m h a s i n d i v i d u a l u n i t s
          u n i t s h a v e l o w e r e n e r g y o p e r a t i n g c o s t s and r e q u i r e
                                                                                                        w i t h thermostats i n t h e classrooms.
          less s k i l l e d m a i n t e n a n c e p e r s o n n e l .                                  A c e n t r a l c o n t r o l system automatically t u r n s t h e
                                                                                                        HVAC u n i t s o n and o f f e a c h d a y . O v e r r i d e t i m e r s
     ENERGY MANAGEMENT CONTROLS
                                                                                                        provided a r e protected with a locked cover.
                                                                                                        Each c l a s s r o o m h a s a n o p e r a b l e window f o r some
               Energy management c o n t r o l s a r e e s s e n t i a l t o
                                                                                                        natural ventilation.
     e n e r g y e f f i c i e n t o p e r a t i o n s i n s c h o o l s . The s c h o o l s
                                                                                                        The windows a r e t i n t e d t o c o n t r o l s o l a r g a i n .
     w i t h t h e l o w e s t o p e r a t i n g c o s t and u s a g e t h a t t h e
                                                                                                        O u t s i d e make-up a i r i s p r o v i d e d f o r k i t c h e n hood
     a u t h o r s have o b s e r v e d a r e t h o s e w i t h c o n t r o l s t o
                                                                                                        t o reduce exhaust of conditioned a f r .
     a u t o m a t i c a l l y s c h e d u l e t h e o n / o f f o p e r a t i o n o f in-
                                                                                                        D a y l i g h t i n g i s p r o v i d e d i n t h e commons a r e a which
     d i v i d u a l s p l i t - s y s t e m D t y p e HVAC s y s t e m s . Pay-
                                               X
                                                                                                        a l s o s e r v e s a s a c a f e t e r i a and a u d i t o r i u m .       (ca-
     back of a u t o m a t i c e n e r g y management c o n t r o l s i n
                                                                                                        fetorium).
     s c h o o l s w i t h c e n t r a l s y s t e m s i s v e r y s h o r t . For
                                                                                                        The c a f e t o r i u m a l s o h a s i n d i r e c t H I D l i g h t i n g .
     example, payback f o r one h i g h s c h o o l was r e c e n t l y
                                                                                                        Classroom l i g h t i n g i s u n i f o r m and l e v e l s a r e
     observed t o b e less t h a n e i g h t months f o r a $17,000
                                                                                                        a p p r o x i m a t e l y 70 f o o t c a n d l e s .
     c o n t r o l system w h i l e r e c e n t a n a l y s i s on a n o t h e r
                                                                                                        Reduced w a t t a g e e n e r g y e f f i c i e n t f l u o r e s c e n t i
     c e n t r a l HVAC s y s t e m p r o j e c t i n d i c a t e d a payback
                                                                                                        l i g h t i n g is i n s t a l l e d i n t h e classrooms, h a l l s .
     of 2.2 y e a r s .                                                                                 and o f f i c e s .
                                                                                                        High p r e s s u r e sodium l i g h t i n g p r o v i d e s i l l u m i n a -
               Keys t o s u c c e s s f u l e n e r g y management c o n t r o l
                                                                                                        t i o n f o r t h e parking l o t .
     systems i n s c h o o l s a r e s i m p l i c i t y o f d e s i g n and                            S k y l i g h t s p r o v i d i n g d a y l i g h t i n g a r e double-walled
     t r a i n i n g of s c h o o l p e r s o n n e l .                                                 t y p e t o m i n i m i z e h e a t l o s s and g a i n .
                                                                                                        The r o o f s y s t e m i n c l u d e s a b u i l t - u p r o o f w i t h
     LIGHTING                                                                                           one i n c h r i g i d i n s u l a t i o n . I n a d d i t i o n , s i x i n -
                                                                                                        c h e s of f i b e r g l a s s b a t t i n s u l a t i o n i s i n s t a l l e d
             Energy e f f i c e i n t l i g h t i n g d e s i g n f o r s c h o o l s
                                                                                                        above t h e l a y - i n c e i l i n g s .




    Proceedings of the Second Symposium on Improving Building Systems in Hot and Humid Climates, College Station, TX, September 24-26, 1985
                                                                                                                ESL-HH-85-09-16


    .   Vestibules are provided at the entrances.                           Vestibule at main entrance which faces south.
                                                                            Indirect HID lighting in cafeteria.
        These energy efficient features were incorpor- '                    Reduced wattage energy efficient fluorescent
   ated as cost-effective energy conservation measures                      lighting system in classrooms and offices.
   without any additional penalty on construction costs.                    HID (metal halide) lighting in gym with multiple
   Satisfied with these results. Whitehouse I.S.D. incor-                   keyed switching controls.
   porated some of these same features during remodeling                    Outdoor lighting is high pressure sodium.
   work at four other campuses.                                             Energy efficient individual split-system heat
                                                                            pumps for classrooms and offices. Efficient air-
    ENERGY EFFICIENT ELEMENTARY SCHOOL        -   TATUM I.S.D.              duct system resulted in low fan horsepower re- '
                                                                            quirements.
        Tatum I.S.D. opened a new modern energy efficient                   A central natural gas fired boiler provides hot
   school on September, 1984. Many energy efficient                         water for space heating in zones with high fresh
   features were incorporated into the unique school                        air and heating loads.
   design. Team work and cooperation between the                            Outside make-up air is provided for'the kitchen
   teachers, administration, architects, and consulting                     hood.
   engineers resulted in adapting passive solar features                    The roof system includes a built-up roof on three
   and daylighting to create a pleasant attractive en-                      inches of rigid insulation.
   vironment in a central learning center, cafetorium,                      Efficient utilization of space.
   multipurpose gym area, and classrooms.                                   Economizer cycle on gymnasium, dressing areas.
                                                                            and cafetorium
          Other special energy efficient features include:
                                                                         CONCLUSIONS
        Built-up roof on one-half inches of rigid insu-
        lation. Six inches of fiberglass batt insulation                      Energy efficient schools are "not an accident".
        is also installed above the lay-in ceilings.                     They require integrated programming, planning, and
        Efficient utilization of space with some areas                   design with energy performance as a priority. A
        serving multiple purposes.                                       coordinated team effort involving the architect,
        A central microprocessor control system automati-                school administrators, and engineer can result in
        cally turns the HVAC system on and off.                          significantly reduced operating costs over the
        Energy efficient individual air-conditioning units               lifetime of a building.
        are provided for each classroom. The thermostat
        is located in the classroom.
        HVAC zones having higher fresh air and heating
        loads are heated by a central natural gas fired
        boiler providing hot water to coils in the air-
        handlers.
        Outside make-up air is provided for the kitchen
        hood.
        Parking lot lighting is high pressure sodium.
        Energy efficient indoor lighting systems include
        indirect HID lighting in the cafetorium. The
        multi-purpose gym has HID lighting also.
        The windows in the classrooms are positioned for
        some daylighitng, but their location also prevents
        students from being adjacent to cold glass.
        An operable window is provided in each classroom
        to provide some natural ventilation.
        Skylights provided are double-walled.

         During a recent site visit to the campus, phy-
    sical education classes were being conducted inside
    the multi-purpose gym with all light fixtures turned
    off.

    ENERGY EFFICIENT JUNIOR HIGH       -   PINE TREE I.S.D.

         Pine Tree 1.S.D.Is new 145.933 square foot ju-
    nior high school had an energy performance of 28,499
    BTU's per square foot (site values) and enerpy cost
    of fifty cents per square foot during the first year
    of operation. This demonstrates that the D.O.E.
    energy perfo5mance guideline of 48.000 BTU1s per
    square foot for secondary schools in the schools
    geographic region is achievable and practical. Energy
    conservation measures incorporated to achieve the
    energy efficiency includes the following:

    .   Daylighitng in central lobby area and gymnasium.




Proceedings of the Second Symposium on Improving Building Systems in Hot and Humid Climates, College Station, TX, September 24-26, 1985
                                                                                                                ESL-HH-85-09-16


                                           SEQUENC       OF A BIUILDING PROGRAM
                                                        hT                        r
                                                               i
                                                               u
                                                            5
                                                            V
                                                               8
                                                            ,
                                                            F
                                                            H
                                                          0 4

                                                          H%
                                                          W 0
                                                          E U
                                                            u
                                                          H 4


                        Establish Needs                     1
                        Facilities Survey                   1
                        Educational
                        Program                             1
                        Public Information
                        Campaign
                        Property Aquisition                 -.
                                                         cont
                        Architectural
                        Program                             1
                        Schematic Design
                        and Budget                        1.5
                        Financial Program                  1
                        Bond Election                      2
                        Design Developement               1.5
                        Construction
                        Documents                           3
                        Advertise for Bids                  1
                        Award Contracts                   .5
                        Bond Sales                         2
                        Construction                      14
                        Equipment and
                        Furniture
                        Installation                        1
                        Occupy New
                        Facilities

                  Average Time To Complete Program                        -   22-24 mo.



                                                                      Figure 1




                                                                   no.r




Proceedings of the Second Symposium on Improving Building Systems in Hot and Humid Climates, College Station, TX, September 24-26, 1985
                                                                                                                ESL-HH-85-09-16



                                                 FIRST COST COMPARISONS
                                                      HVAC SYSTEMS
                                                          1984

                                                                                     Initial Cost
                                 System                                             Ranking ( % of
                                                                                    central chilled
                                                                                    water systen~k

                                  - water system*pipe chilled
                                    Central four
                                  - Hydronic heat pump
                                    system
                                  - Rooftop roof top system
                                             multi-zone units
                                  - VAV-DX system DX w/hot
                                  - Split
                                           (gas) heat
                                  - water top heat pump zone
                                    Roof
                                  - Roof top DX single
                                  - Split system heat pump
                                            zone
                                  - singlesystem DX w/gas heat
                                     Split
                                  - Split system DX w/electric
                                     resistance heat
                                  *Includes Multi-zone, Dual Duct VAV, fan coil, and
                                  single zone systems.


                                                             Figure 3



                                     ENERGY        OPERATING       COST     COMPARISONS
                                  HVAC                                              SYSTEM
                                                                                   Cost Ranking
                                 System                                           (Most Efficient
                                                                                    -
                                                                                    to Least)
                                  Split system DX w/gas furnace                             10
                                  Split system DX w/ heat pump                               9
                                  Split system DX w/hot water
                                    (gas) heat
                                  Split system DX w/electric
                                    resistance heat
                                  Roof top heat pump single zone
                                  Roof to DX single zone
                                    w/electric heat
                                  Hydronic heat pump system
                                  VAV-DX roof top system
                                  Roof top multi-zone unit
                                  Central four pipe chilled
                                    water system



                                                             Figure 4




Proceedings of the Second Symposium on Improving Building Systems in Hot and Humid Climates, College Station, TX, September 24-26, 1985
                                                                                                                ESL-HH-85-09-16




                                            MAINTINACE SKILL REQUIRED
                                               (Highest to Lowest)
                                   Central four pipe chilled water system
                                   Hydronic heat pump system
                                   Roof top multi-zone unit
                                   VAV-DX roof top system
                                   split System DX w/hot water (gas) heat
                                   Roof top heat pump
                                   Roof top DX-single zone
                                   Split system heat pump
                                   Split system DX gas heat
                                   Split system DX electric heat


                                                          Figure 5




Proceedings of the Second Symposium on Improving Building Systems in Hot and Humid Climates, College Station, TX, September 24-26, 1985