Belimo Holding Ag · SIX:BEAN
Belimo — Technical Presentation (March 2018)
20 slides from Belimo's technical presentation, Mar 27, 2018
Slide 1: Correcting Low ∆T in Buildings with District Cooling
Correcting Low ∆T in Buildings with District Cooling Steve Rybka 3/27/2018 1
Slide 2: Agenda
District Cooling and ∆T Correction Agenda • What is Low ∆T Syndrome? • Coil Design & Performance • Why maintain ∆T at the point of water to air hear transfer? • Common District Cooling Building Connections • Directly connected buildings • Decoupled buildings • Causes of Low ∆T Syndrome • Low ∆T and
Slide 3: What is Low ∆T Syndrome?
District Cooling and ∆T Correction What is Low ∆T Syndrome? Q(Btu/h) = 500𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥𝑥∆𝑇𝑇 Low ΔT syndrome is the result of the inefficient use of chilled water at the point of consumption Steve Rybka 3/27/2018 3
Slide 4: Coil Design & Performance
District Cooling and ∆T Correction Coil Design & Performance Steve Rybka 3/27/2018 4
Slide 5: Why maintain ∆T at the point of water to air heat transfer?
District Cooling and ∆T Correction Why maintain ∆T at the point of water to air hear transfer? • Utilities rates change based on ∆T • The lower the ∆T the higher the rate • Rates can increase during demand hours • Reducing the flow transfers problems from the plant to the buildings • Cooling coils s
Slide 6: Direct Connected Buildings: booster pump
District Cooling and ∆T Correction Direct Connected Buildings • Directly connected building with a booster pump • Adds head pressure to guarantee flow but could compromise flow to other buildings on the loop Steve Rybka 3/27/2018 6
Slide 7: Direct Connected Buildings: pressure regulating valve
District Cooling and ∆T Correction Direct Connected Buildings • Directly connected building with a pressure regulating valve • Valve reduces the supply side pressure to coils & valves Steve Rybka 3/27/2018 7
Slide 8: Direct Connected Buildings
District Cooling and ∆T Correction Direct Connected Buildings • Directly connected building • Reliant on the pressure provided by the distribution system Steve Rybka 3/27/2018 8
Slide 9: Direct Connected Buildings: booster pump & bypass
District Cooling and ∆T Correction Direct Connected Buildings • Directly connected building with booster pump & bypass • Increases pressure as needed at higher loads Steve Rybka 3/27/2018 9
Slide 10: Decoupled Buildings: crossover control valves
District Cooling and ∆T Correction Decoupled Buildings • Decoupled building with entering water and crossover control valves • Inlet valve regulates water flow on the supply side and the valve in the crossover is used to regulate water temperature Steve Rybka 3/27/2018 10
Slide 11: Decoupled Buildings: return water temperature control valve
District Cooling and ∆T Correction Decoupled Buildings • Decoupled building with return water temperature control valve • Circulates water until it is at the design return water temperature Steve Rybka 3/27/2018 11
Slide 12: Decoupled Buildings: heat exchanger
District Cooling and ∆T Correction Decoupled Buildings • Decoupled building with a heat exchanger • Fully separates the building from the distribution loop, there is a potential for heat transfer loss at the heat exchanger Steve Rybka 3/27/2018 12
Slide 13: Pump Affinity 10°∆T vs 12°∆T
District Cooling and ∆T Correction Pump Affinity 10°∆T vs 12°∆T @ 100 Tons 𝟏𝟏𝟏𝟏𝟏𝟏 𝒙𝒙 𝟐𝟐𝟐𝟐 GPM = 𝟏𝟏𝟏𝟏𝟏∆𝑻𝑻 𝟑𝟑 𝑮𝑮𝑮𝑮𝑮𝑮 = 𝟐𝟐𝟐𝟐𝟐𝟐 𝟐𝟐𝟐𝟐𝟐𝟐/𝟐𝟐𝟐𝟐𝟐𝟐 =1.728 73% more horsepower 𝟏𝟏𝟏𝟏𝟏𝟏 𝒙𝒙 𝟐𝟐𝟐𝟐 GPM = 𝟏𝟏𝟐𝟐°∆𝑻𝑻 2°F decrease in ∆T 𝑮𝑮𝑮𝑮𝑮𝑮 =…
Slide 14: Causes of Low ∆T
District Cooling and ∆T Correction Causes of Low ∆T • Equipment designed for different ΔT’s • Three way valves allow chilled water to bypass coils at part load • Resetting the supply air temperature set point above design can lead to unstable control and low return water temperature • Coils that are
Slide 15: Causes of Low ∆T
District Cooling and ∆T Correction Causes of Low ∆T • Oversized chillers, pumps, coils, control valves and piping • Controlling the chilled water valve using only the air sensor • Manual balancing only addresses one flow condition • Systems rarely run at full load causing overflow at part load • Hyd
Slide 16: Causes of Low ∆T: laminar flow
District Cooling and ∆T Correction Causes of Low ∆T • Laminar coil flow reduces overall heat transfer capacity of the coil • Laminar flow occurs when water flows in parallel layers and doesn't mix. • When water travels through a coil too slow it causes laminar flow. • The heat transfer efficiency of
Slide 17: The Belimo Energy Valve
District Cooling and ∆T Correction The Belimo Energy Valve™ can measure flow, temperature and calculate ∆T. With this information adjustments can be made to maximize the efficiency of hydronic coils. Actuator & Controller Flow Meter Temperature Sensors Control Valve Steve Rybka 3/27/2018 17
Slide 18: Original Basis of Design, June 1984
District Cooling and ∆T Correction Original Basis of Design. June of 1984 • 15 Story High Rise Office Building • 15 Air Handlers • GPM Ranges from 71.2 – 86.5 • 15°F Design ∆T • Average Building ∆T Between 8°F - 11°F • Average Monthly Low ∆T Penalty of $1,090.00 • Maximum Average Flow in Excess of 5
Slide 19: Project Metrics
District Cooling and ∆T Correction Project Metrics Project Scope Install 15 Energy Valves Cost to Implement $53,474.00 Annual Cost Avoidance $22,821.00 Simple Payback 2.4 Years Return on Investment 40% Min/Max Average GPM Reduction >200 GPM Steve Rybka 3/27/2018 19
Slide 20: Thank You
THANK YOU mae BELIMO Steve Rybka