hvac, motors & controls - nv energy...3 ways to increase chiller efficiency • chilled water...
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HVAC, Motors & ControlsOptimize Your HVAC System
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Free technologySmart Networked Thermostats Free equipment and installation Centralized Management of Heating and Cooling
Equipment Monitor & control from a centralized web portal Typical 10% heating and cooling energy savings Must participate in limited number of Community
Energy Events
Must participate in 15 community energy events or 75% of all events, which ever is less
At least 75% of devices have to play to get credit for event
Events are 2-hours and held 1pm -7pm (typically 3pm-5pm)
South – 1 June – September 30
No events the day before or on holidays – 2 event max per week
Facility can’t have a Energy Management System
Prefer 5 or more thermostats
Participation requirements
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SolarGenerations
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SolarGenerations incentives
Expected Performance- Performance-BasedBased Buydown Incentive
Up to 25 kW size 25 kw – 500 kW size
• Public, Low Income, Non-profit $490 per kilowatt $0.0527 per kWh
• Residential, Commercial, Industrial $245 per kilowatt $0.0264 per kWh
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SolarGenerations offering
• Continuously open
• Eligible for system size up to 500 kW
• Incentives are paid up front for small systems (EPBB) and over time for larger systems (PBI)
Agenda
HVAC
Chiller/RTU
Motors
Pumps
Fans
Controls
VFDs
Programming
Sequence of operations
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Oversizing
On average, building fan systems in the US are oversized by 60%*
Most chillers are oversized by 50-200%**
Spend < 1% of operation at full load
Don’t add “safety factors” when sizing or selecting
Better dehumidification
Smaller equipment will dehum better, allowing higher cooling setpoints
Less temperature swings
Equipment runs event cycles instead of rapid on… off… on…
Lower first cost
Less energy (kWh) consumption and lower demand (kW) charges
*John Hopkins Univ. AICGS Policy Report **US EPA Report “Good Energy Management is Good Business”
Chillers
Chiller illustration
Energy Design Resources
3 Ways to increase chiller efficiency• Chilled water reset
• Supply 42-44o
• Return 54-55o
• VFD on chiller (15-25% savings)• Premium motors for pumps (VFDs)
Chiller capacity
Energy Design Resources
Chiller power kW/ton
Automated Buildings
Modern day chillers 0.45
Chiller comparison
Chilled water economizer
Energy Design Resources
HVAC systems (RTUs)
Schematic
Carrier
Advanced building strategies
US Department of Energy
Decision tree
RTU planning strategy
Assessment
Age II
Maintenance
Condition Equipment Repair
Upgrade
I Inventory
Energy Savings Retrofit Cost Control
Planned Replacement
$$$ to bottom line
Optimize
Planning
Sizing Purchasing III
Replacement
Scheduling
Data plate
What is your equipment baseline?
Investing in aged equipment may not be the best option
Review past service invoices for problem units
Identify the “worst of the worst”
Formulate a plan
Replacement approach
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Energy efficiency consumption
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Efficiency comparison
Controls
Advanced RTU controllers will have the best performance under the following conditions:
Existing RTU
Constant speed supply fan operation
Greater than 7.5 tons (evaporator fan >2 hp)
At least 5 years remaining life
Existing building
More than 50 hours per week operation
High electricity rates (over $0.10/kWh blended rate)
Located in a climate with significant swing seasons
Advanced controls
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Control devices
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RTU retrofit controls
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VFD cost
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Fan law curve
NEX REV
Average VFD project savings for retail application
12 RTUs, 20 tons each
134,760 kWh/year savings
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VFD savings
Retrofit to fans
Varies the power input to motor
On average, building fan systems in the US are oversized by 60%
If a motor running at 100% speed costs $1,000/month, what about:
Running at 75% speed = $420
Running at 50% speed = $125
Due to the Affinity Laws
Soft start means less wear and tear on couplings, belts, and motors –lower demand charge
Payback less than 18 months
*John Hopkins Univ. AICGS Policy Report
VFDs
Economizers
Many systems have never been commissioned at all
Perform functional performance tests
Economizer dampers and controls inoperative or in poor condition
Test bi-annually, repair or replace
Sensors not recalibrated on regular basis (especially enthalpy and CO2sensors)
Recalibrate sensors bi-annually
Other issues
Systems have been locked out by operator
Scheduling is not optimized (sometime running 24/7)
Economizer control not optimal (too high of OA setpoint)33
Economizer optimization
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Economizer hours
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Economizer savings
ACCA
CO2-based Demand Control Ventilation
(DCV)Now part of the building code in many municipalities
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Numerous studies confirm that correct ventilation: Increases productivity
Improves occupant/customer satisfaction
Helps prevent sick building syndrome health affects
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CO2 studies
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CO2 levels
ASHRAE
Easy to retrofit
Adaptive intelligent recovery
2-stage stat for integrated economizer as 1st stage
Shut off ventilation during unoccupied hours
Internet accessible
Payback less than 6 months
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Programmable T-stats
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Pelican wireless
Motors
Smaller Motors
Shaded Pole
Permanent Split Capacitor (PSC) Motors
Electronically Commutated Motor (ECM)
Efficiency of SP vs. PSC vs. ECM
Motor Type SP PSC ECM
Watts Input 43.8 29.0 20.0
Watts Output 13.2 13.2 13.2
Watts Loss 30.6 15.8 6.8
Efficiency 30.1% 45.5% 66%
ECM Watts Saved 23.8 9.0 -
kWhrs Saved/year 197 74.5 -
Savings at $0.10/kWhr $19.70 7.45 -
*Conservatively assumes case runs 23 hours per day and 360 days per year for a total running time of 8280 hours per year.
Range from 60-75% efficiency
Quiet, less heat, multi-speed or variable
Wide range of operability choices compared to older AC HVAC motors
Electronically Commutated Motors (ECMs)
Can start and stop slowly, speeds can be easily adjusted
1.5 to 4 times in cost
Commonly <1 -10 HP
Switched-reluctance motors (SRM)
Electronically Commutated Motors (ECMs)
Pics from Johnson Controls
Premium vs. standard
Success stories
Silver Legacy Resort Casino
Installed: Lifting station pumps with VFDs
Cooling tower motor VFDs that modulate load from 20% to 100%
Logging was conducted pre- and post-installation for energy savings verification
Incentive payment: $14,400.00
kWh savings: 82,571.11 annual
Installed:
Upgraded controls and repaired economizer stuck in open position
Ductless split for the 10x12 server room
Increased comfort for office space and reduced energy consumption on the 80 ton system
Incentive payment: $6,497.20
kWh savings: 107,930
Nevada State Bank
Installed:
New condenser water pumps and chilled water pumps
Butterfly isolation valve to enable free cooling using the lake and the cooling towers at the same time
Mezzanine pump to deliver additional GPM while under heat exchanger modes
Energy savings derived from better use of equipment in the plant and utilization of variable speed drives
Incentive payment: $117,199.85 (tiered)
kWh savings: 2,313,248
Grand Sierra Resort
