HVAC Systems for Low Energy Buildings 50% More Efficient, LEED PLATINUM . IGS Building Case Study: HVAC Strategies (How) HVAC Technologies (What) Financial Metric for Cost-Effectiveness Barriers Questions ??? ? What would you do differently ? Perspective of presenter (EE Evangelical) More info: ASBO Publication & tour Burning Questions??
IGS: ENERGY-OPTIMIZATION RESULTS• IGS achieved about 50% more efficiency than the baseline 90.1, 2004 energy code. Meet ‘Architecture 2030’ goal at time of design.• Cost Effective: Achieved about 50% at about the same or less cost for 30% efficiency. Energy Investment Savings Pays for the Increase in Mortgage Cost.• This was done in spite of sub-optimal orientation (N/S vs. E/W), that hurts passive design & day- lighting effectiveness with harshest E &W glare.• Synergistic energy savings and first cost savings occurred from diligently pursuing optimized energy efficiency.
Speaker’s perspective:Energy Consultant to IGSMaster of Env. Science, (Miami U.)Major: Energy (Individualized Curriculum):Solar Architecture, Mech Eng, EconomicsBS: Math & Chem. E (OU)15 yrs: Innovative Energy Research &Demonstration NLC/DOE Funded Grants10 Yrs: Facilities Management, O&M (driver)& New Construction –LEED APAbove as City of Columbus Energy Coordinator
Speaker’s perspective: Experience– 15 Yrs. NLC/DOE research & demonstration grants: USDOE funded Columbus Energy Plan, 300 City building’ audits, energy bond package, ‘portfolio manager’ BTU/SF, Energy Use of Ventilation IAQ, Green Lights project saved $500,000 & 10 tons CO2, demonstrated VFD’s, DDC, O&M, etc.- Energy Awards: Governor’s Energy Award, HUD Award, OPFMA Award –Ohio Public Facilities award, NLC-ETF Award –National League of Cities Energy Task Force- Published Results in Peer-Reviewed Energy Science: ASHRAE (heating & cooling engineers) Journal, AEE –Assoc of Energy Engineers, IAQ Journal etc.
LEED is Great, but does not guaranteeoptimal efficiency:• LEED is not an energy optimization procedure, it is a great Green Building Rating System.• LEED only requires 14% more efficient than the energy code.• Many LEED Certified & Silver are about 25% more efficient, many Gold about 30% more.
LEED is Great, but does not guaranteeoptimal efficiency:• IGS did Platinum Right: built on the foundation of high (50%)energy efficiency• INTENT of LEED is Integrated Design• Low Energy Requires: Energy-Efficiency-Optimized Integrated Design• Primary tool: Iterative Energy Simulations
Commercial vs Residential:Interior Core vs Perimeter
Commercial Building Energy UseWhy Can’t Just Pick a Super Efficient HVAC Systemto get optimized efficiency:heating + cooling = only 17%, so if cut it in half, stillnot optimized efficiency for whole building.
VAV vs. DOAS with ER =cools & shuts off vs. re-heating.
Technologies to improve Energy Efficiency:• Not an exhaustive list• A Flurry of energy efficiency activity, with all of these technologies improving and competing at this time.• Good design requires identifying the strengths and weaknesses of each technologyThose In Green on next slides= what did in IGS’ design @2008-09.Those In Red= what would do differently today=Raise goal to 80%, achieve 60% cost effectively= Arch 2030 Challenge, Ed Mazria, who wrotePassive Solar Home Book, 1979 Rodale Press
Technologies to improve Energy Efficiency: Efficient lighting LED (bulb changing maintenance) Day-lighting Open ceiling Light shelves Exterior shading Diffusers Cloth Baffles
Technologies to improve Energy Efficiency: Roof monitors Diffusing panel Day-lighting Computer simulation models: Radiance, Daysim Physical day-light models Scotopic (OSU test, NASA Marshal Flight Center) (sky blue+tint) vs Photopic• Envelope: triple element glass• DOAS• ER-V=Energy Recovery Ventilation (humidity&drybulb)• AF hi-eff fan• IAQ-DCV• “Sees cooking” kitchen hood exh fan control• Solar Preheat of outside air/ventilation air• Solar thermal
Technologies to improve Energy Efficiency:• Geothermal Well field Water well Storm water pond Ice prevention (cascading) vs snow melt• Radiant Floor• VRF-VRV: Variable Refrigerant Flow/ Variable Refrigerant Volume• Ice storage: large commercial• Ice storage: Small size, 5-15 ton
Technologies to improve Energy Efficiency:• Micro-turbine (100 units coal at power plant, only yeilds 25 to 30 units at building)• Chilled Beams• Hi Efficiency Fan Coils• Underfloor systems• Natural /hybrid ventilation.• CFD modeling• Green Roofs: storm water, insulation, CO2• Wind-building integrated wind• Solar electric-smart grid
Technologies to improve Energy Efficiency:• + ‘regulars’:• Plug loads: -All computers in computer center, only LED Monitors @Desks -Refrigerators, coffee pots -USB plug loads - timers• DDC controls• Commissioning• Chillers• Boilers & at low temp coil =94% Efficiency.• O&M• IAQ• Experience:• Knowledgeable & know how to evaluate vs Know It All
Technologies to improve Energy Efficiency:• As the list above demonstrates, it is not possible for the building administrator to become an expert on all of these issues.• Instead, Requires an Energy-Efficiency-Optimized Integrated Design• Primary tool: Iterative Energy Simulations (need a simulation for LEED energy points anyway, so just do more and earlier +do from 3D BIM)
Energy Efficiency• “If one views efficiency as an energy resource, then it cost 3 to 10 times less than any other energy resource, including renewable energy.” (Charleston SC Green Plan)• “When you look at the options ...the cleanest, fastest, cheapest, safest, surest energy supply option continues to be …efficiency of energy end use”. John Holdren, PhD Presidents science adviser
Energy efficiency• It is the greenest energy because it’s greener to not use energy at all, than to use energy.• Optimizing energy efficiency first, is critical for achieving cost effectiveness for any renewable energy application.
Right way to simulate:• 1st Simulate building efficiency, Building is more permanent.• Evaluate all options, holding HVAC constant at 90.1 code system.• Select efficiency package by shorter paybacks.• Last, simulate HVAC options & renewables.
Dont limit it to only short paybacks• Even a 15 year payback is OK with building life of 40 to 100 yrs.• 1st year energy savings is the investment cost divided by 15 yrs.• Cash flow cost is a fixed annual amount added to mortgage.• Annual energy savings will increase as energy costs rise.
Financial Metric: Years to positive cash flow:• The Critical Financial metric is ‘years to positive cash flow‘.• Even for a worse case 15 yr. payback, the increase paid on the mortgage over the 1st 3 years is insignificant.• This is true regardless of the technology: because this analysis is independent of the technology.
Financial Metric: Years to positive cash flow:• Energy Efficiency Investments: The savings pays the additional mortgage cost.• Shown on the next 2 slides for an additional mortgage amount of $630,000 for a geo-thermal well-field added to the original $20,000,000 estimated building cost.
Case study: invest @ 15 yr payback:$630,000 for a geo-thermal well field added to a $20,000,000 building: 1st year energy savings is cost */* 15= $630,000 */* 15yrs = $42,000/ 1st yrCost of $630,000 added to mortgage:@ 30 yr mortgage =$5.93/mo. per $1000 borrowed=$5.93 x 630 thousands =$3,736/mo.= $44,831/ yrBarriers: Developer buildings pass cost totenant; barrowing capacity, setting priorities.
Example of Energy Optimization Process:• Next 3 slides show an example of how it works.• 1st is ‘typical high-efficiency’, achieves about 28% more efficient.• 2nd is aggressive energy efficiency: continuing to do all efficiency options with longer paybacks, to achieve about 45% efficiency.• 3rd Last thing, after greatly reducing its size and cost, is adding a high efficiency HVAC system.
IGS Energy Optimization 1 of 5:• Lighting reduced 50%, +day-lighting reduced additional 25% =62.5% total reduction. Commercial bldg. lighting is biggest cooling load, so this greatly reduced AC size, fan energy, & cost. Cost= Lighting cost less than original design lighting + Day-lighting system reduced blinds SF & their cost; slight add for day-light diffusing glass.• Plug loads reduced by 50+% by moving all computers to computer center =greatly reduced AC size & its cost.
IGS Energy Optimization –Continued 2 of 5:• Once all computers were moved to a computer center, it had to be cooled continuously; that cooling generated heat, which was put into the heat- pump loop to provide ‘free’ heat recovery. Very quick payback.• Ventilation/IAQ: Heat/cool/humidity from exhaust recovered into outside ventilation air (total energy recovery). Cost: typical payback about 7 yrs + greatly reduce heating & cooling loads & their equipment size & cost.
IGS Energy Optimization –Continued 3 of 5:• Resultant heating & cooling size was reduced about 45%, greatly reducing cost of geo-thermal heat pump HVAC system.• Site energy 1: Put heat exchange coils in the pond to reduce size of geo-well field and save on first cost.• Site energy 2: Put fountain in pond to do evaporative cooling and use it as a water tower to reduce costs.
IGS Energy Optimization –Continued 4 of 5:• Site energy 3: Hydro-geology assessment favorable, so used water-well with injection-well and isolation coils to eliminate corrosion, to improve geo-thermal efficiency and totally eliminate ground-coupled well field, and save that $630,000.• Net Result: With synergistic effects of optimized-energy-efficiency design, achieved 45%+ efficiency with less first cost than most systems that save 30% or less!
IGS Energy Optimization –Continued 5 of 5:• Only after energy efficiency is optimized should more expensive renewables be added; remember, the Greenest Energy is Energy Efficiency because it is greener to not use energy at all.• Site energy 4: Roof top Photovoltaics to achieve about 50% total energy reduction vs. 2004 90.1 energy code.• Tax deduction for high efficiency, about 1.75/sf. =$175,000 =about $60,000 actual tax reduction more than pays for additional design cost and energy consultant.
If you can’t afford energy efficiency….• Then surely can’t afford higher energy bills.• Cant afford to come back later=cost 5 to 10 times more.Barriers? Local examples.talk the talk, vs walk, vs run= commitment & vision.Energy consultant responsible toowner & free = more than paid forby tax deduction
An effective strategy for maximizingenergy efficiency:• Hire an independent energy consultant as the owner’s representative for overseeing and achieving energy efficiency• extensive experience with energy simulation• previously achieved 40 to 50% energy efficiency, cost-effectively
Energy consultant responsibilities• Simulating, evaluating, & tracking progress to achieve energy goal• Regularly updates owner on status throughout the project• Critical since an aggressive goal often inadvertently neglected or water down, as result of the multitude of issues in designing a building, especially a green building.
Important advantage of using anindependent energy consultant:• Can use trusted A&E even if have not yet achieved a high efficiency design.• An energy consultant specializing in energy simulation and cost benefit analysis can be an asset to the A&E firm.• Can also be less expensive because that is all they do; unlike the A&E who must design and specify every aspect of the building.
Procedure Summary1. Define green energy as maximum energy efficiency at lowest cost.2. Set an aggressive goal: 50% energy reduction over the energy code for each and every area of building energy use.3. From the beginning of conceptual design, use energy simulations to assess all energy efficiency options with paybacks of 15 years or less
Procedure, cont:4. Simulate & assess building efficiency prior to any improvements to the heating and cooling plants or the addition of any renewable energy.5. Select best payback options, then simulate Higher Efficiency HVAC &or renewable energy6. Hire experienced independent energy consultant as the owner’s representative for overseeing and achieving energy efficiency
Joseph Ventresca, MS Energy, LEED APMaxGreen Energy614-309-7797ASBO Paper: email title=‘IGS Paper’Tour: 1 to 4 Sunday, Oct 2, 20116100 Emerald Parkway, Dublin, OH. 43016