Thank you, sponsors Our online sponsors PLATINUM GOLD 1 - - PDF document

▶
thank you sponsors
SMART_READER_LITE
LIVE PREVIEW

Thank you, sponsors Our online sponsors PLATINUM GOLD 1 - - PDF document

Sep 22, 2022 529 likes •605 views

6/28/2016 OPTIMIZING CONDENSER PERFORMANCE Presented by: Rob Travis, P.E. 1 Thank you, sponsors Our online sponsors PLATINUM GOLD 1 6/28/2016 TOP 4 LOW COST CONDENSER ACTION ITEMS 1. Reduce Condensing Pressure 2. Enable Wet Bulb

slide-1
SLIDE 1

6/28/2016 1

OPTIMIZING CONDENSER PERFORMANCE

Presented by: Rob Travis, P.E.

1

PLATINUM GOLD

Our online sponsors

Thank you, sponsors

slide-2
SLIDE 2

6/28/2016 2

TOP 4 LOW COST CONDENSER ACTION ITEMS

  • 1. Reduce Condensing Pressure
  • 2. Enable Wet Bulb Approach
  • 3. Proper Sequencing
  • 4. Optimize Performance

3

Courtesy: Evapco

  • 1. REDUCE CONDENSING PRESSURE

4

  • Rule of thumb savings:
  • 1.5% compressor savings per degree‐F reduction in

condensing temperature

  • Reducing minimum condensing pressure
  • Action: Eliminating barriers to minimum allowable

pressure

  • Reducing condenser approach
  • Action: Increase condensing capacity

Important: Reducing approach and minimum pressure are completely separate issues, not to be confused or overlapped.

slide-3
SLIDE 3

6/28/2016 3

MINIMUM CONDENSING PRESSURE

5

Shaded area represents decrease in energy by lowering the pressure setpoint to the minimum achievable value

  • Target of 90 (58°F) to 110 psig (68°F) psig for most

systems (and in most climate zones)

10 20 30 40 50 60 70 80 90 100 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Temperature (°F) Wet Bulb, °F Minimum Condensing Baseline Condensing

ACHIEVABLE CONDENSING PRESSURE

6

slide-4
SLIDE 4

6/28/2016 4

COMMON BARRIERS TO CONDENSING PRESSURE REDUCTION

7

  • Hot gas defrost
  • Heated zones
  • Icing or other winter issues
  • Water defrost and common sump
  • Oil separator performance
  • Gas‐powered valves or unloaders
  • Liquid injection oil cooling
  • Screw compressor oil carryover
  • Underfloor heating
  • Pumper drum operation
  • Direct‐expansion coils
  • Process or door hot gas
  • Inadequate liquid pressure to serve loads
  • Concerns about condenser fan and pump energy
  • Misperceptions about volume ratio and efficiency
  • Tradition

Minimum Pressure Setpoint Liquid Injection Hot Gas Defrost DX Coils Oil Separator

  • 2. ENABLE WET BULB APPROACH

8

  • Wet bulb approach is a condensing strategy that strikes

an effective balance between compressor power and condenser fan and pump power

  • Ensures excess condenser power is not used to try to

achieve an impossible condensing pressure based on a high wet bulb temperature

  • Allows the condenser fans to “relax” without sacrificing

compressor power

  • Approach value is based on condenser size and

condition – typically 12°F – 18°F

  • Incremental economic return with larger condensers.

As approach decreases, additional condenser fan and pump power eats into compressor savings

slide-5
SLIDE 5

6/28/2016 5

WHAT IS CONDENSER WET BULB APPROACH?

9

  • Condenser approach is:

Condensing Temperature ‐ Wet Bulb Approach Shaded area represents increase/decrease in energy between approach values

10 20 30 40 50 60 70 80 90 100 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Temperature (°F) Wet Bulb, °F 15°F Approach 25°F Approach

  • 3. PROPER SEQUENCING

10

  • Sequence condenser

to operate: “pump‐fan‐pump‐fan”

  • Pump‐only operation
  • nly provides 10% of

total condenser capacity

  • Fan only operation

provides only 10% to 30% of rated capacity

(Excerpt from Evapco Catalog)

Condenser Dry Operation Multiplier

0% 5% 10% 15% 20% 25% 30% 35% 40% 35 30 25 20 15 10 5 Ambient Temperature (°F) Capacity Multiplier Rating at 90 psig Condensing

Condenser Dry Operation Multiplier

0% 5% 10% 15% 20% 25% 30% 35% 40% 35 30 25 20 15 10 5 Ambient Temperature (°F) Capacity Multiplier Rating at 90 psig Condensing

slide-6
SLIDE 6

6/28/2016 6

MULTIPLE CONDENSER STAGING: PUMP‐FAN‐PUMP‐FAN VS. PUMP‐PUMP‐FAN‐FAN

11

  • Keep the minimum number of

condensers running where medium fan speeds are achieved

  • Be mindful of water treatment

concerns

  • Avoid rapid pump cycling

MULTIPLE CONDENSER STAGING

Pump‐Fan‐Pump‐Fan vs. Pump‐Pump‐Fan‐Fan

  • 4. OPTIMIZE PERFORMANCE

12

Maintain condensers in optimal condition

  • Good water distribution
  • Clean pump strainers
  • Clean out sump tank annually
  • Check spray nozzles
  • Inspect eliminators
  • Stay on top of water treatment
  • Tighten fan belts
  • Ensure purger is functioning
slide-7
SLIDE 7

6/28/2016 7

IMPACT OF SCALE ON CONDENSERS

13

  • Reduce condensing pressure to the lowest limit allowable in

the system

  • Enable wet bulb approach condensing strategy.

Set approach value between 12°F and 18°F

  • Utilizing a Pump‐Fan‐Pump‐Fan strategy optimizes condenser

power

  • Maintaining condensers will result in compressor energy

savings

14

CONCLUSION