APS Chiller Seminar

Don Brandt, CEM-AEE, BEAP-ASHRAE ASHRAE and IEEE Life Member

3/16/2017

Agenda for today • Refrigeration Cycle • Chiller Types and Refrigerants • Compressor Styles • Chilled Water Pumping Systems • Control of Chiller Plants • Improving Chiller/System Efficiency • Maintenance • Absorption Cycle • Questions & Answers – Anytime

Chilled-water System

pump coil

control valve

air-cooled chiller

Refrigeration Cycle

• Review of the Vapor Compression Cycle

Vapor-Compression Cycle

compressor

condenser

expansion device

evaporator

Basic Refrigeration System

compressor

condenser

evaporator

expansion device

discharge line

suction line

liquid line

A

B

C

D

Compressor

low-pressure refrigerant vapor from evaporator

C B

high-pressure refrigerant vapor to condenser

Condenser C

D

refrigerant vapor

liquid refrigerant outdoor

air

Expansion Device

A

D liquid refrigerant

mixture of liquid and vapor refrigerant

Evaporator

refrigerant vapor

mixture of liquid and

vapor refrigerant

B

A

air

Basic Refrigeration System

compressor

condenser

evaporator

expansion device

high-pressure side

low-pressure side

discharge line

suction line

liquid line

A

B

C

D

Chiller Styles

• Air Cooled – Packaged and Split System

• Water Cooled – Small, Medium and Large Tonnage

• Chillers with Evaporative Condensers • Modular Chillers • Packaged Chilled Water Plants

Packaged Air-cooled Chiller

air-cooled condenser compressor

evaporator propeller-type condenser fans

Air-cooled or Water-cooled Low-ambient Operation

air-cooled chiller

subcooler

outdoor air

condenser coil

propeller fan

Air-cooled Condenser

Packaged Air-Cooled Chiller

air-cooled chiller

Remote Evaporator Barrel

condensing unit

remote evaporator

refrigerant piping

liquid/vapor separator

motor

oil separator

condenser

oil supply system

compressor

control panel

evaporator starter

Components of a Helical-rotary Water Chiller

Condenser

baffle

tube bundle

liquid refrigerant

refrigerant vapor

cooling tower water

Evaporator

eliminator liquid distributor orifice system

liquid refrigerant

tube bundle

chilled water return

cooling water

subcooled, liquid refrigerant

subcooler

hot, refrigerant vapor

85ºF [29ºC]

95ºF [35ºC]

Water-cooled Condenser

Shell-and-Tube Evaporator

refrigerant vapor

chilled water return

chilled water supply

tube bundle

baffles

liquid/vapor refrigerant

Shell-and-Tube Evaporator

baffles

Cooling Tower sprays

from condenser

to condenser

sump

propeller fan

outdoor air

85ºF [29ºC]

95ºF [35ºC]

fill

Evaporative Condenser

sump pump

condenser coil

refrigerant vapor

subcooler

fan

liquid refrigerant

water-cooled

• Greater energy efficiency

• Longer equipment life

air-cooled • Lower maintenance • Packaged system • Better low-ambient operation

Air-cooled or Water-cooled Comparison

Modular Chillers

• Typically Water-Cooled, some Air- Cooled

• Modules piped in Parallel from a water flow standpoint

• Compressors: Scroll, Screw and Centrifugal – older may have Reciprocating

Modular Chiller Applications High-efficiency Cooling Only

Simultaneous Heating and Cooling Utilizing Heat Pump

Refrigerants for Chillers

• Scroll and Recip: HCFC-22 , HFC-407C , HFC-410A , HFC-134A

• Helirotor or Screw: HCFC-22 , HFC-134A

• Centrifugal: HFC-134A , HCFC-123 • Future Refrigerants: Ammonia, HFOs • Classified by ASHRAE Std 15 – 2016

Refrigerants of the Future • HydroFluoroolefins – no ozone

depletion and low GWP • R-514A, low pressure, replace R-123

in Centrifugal Chillers, GWP = 2 • HFO-1234yf, medium pressure,

replace R-134a in automotive/transportation, GWP =4

• R-32, high pressure, replace R-410A in VRF, GWP = 675

Refrigerants of the Future

• R-452A, med pressure, replace R-404 in various application, GWP = 1945

• R-449A, high pressure, replace R-22 and R-407 in chillers and unitary, GWP=1282

• R-513A, medium pressure, replace R-134a in air cooled screw chillers, GWP =573

Refrigerants of the Future

• R-452B, high pressure, replace R-410A in unitary, residential and smaller HVAC equipment, GWP = 676

• Suggested reading-Honeywell website under Soltice refrigerants

Refrigerants of the Future

• Also check out websites for Chemours – Dupont and Arkema

• ASHRAE Std 15 -2016 has new classification of 2L for low flammability HFO’s as it relates to safety

• ASHRAE just approved $1.5 Million in research for safety guidelines.

Refrigerants of the Future

• California just announced it will no longer allow any new equipment with R-134a in the state, starting in Jan of 2020.

Refrigerants of the Future

• GWP of current refrigerants. • R-22, GWP = 1700,HCFC • R-123, GWP = 0.02, HCFC • R-134A, GWP = 1300, HFC • R-11, GWP = 4000, CFC • R-12, GWP = 2400, CFC

Refrigeration Compressors

• Reciprocating • Scroll • Helirotor or Screw-One, two and

Three Rotor • Centrifugal

scroll reciprocating

Air Conditioning Clinic TRG-TRC004-EN © American Standard Inc. 2000

helical-rotary centrifugal

Reciprocating Compressor

piston refrigerant vapor

cylinder

discharge valve

rod

suction valve

intake stroke

Reciprocating Compressor

suction valve

discharge valve

compression stroke

Reciprocating Compressor suction opening

motor

piston

cylinder

crankshaft

rod

discharge opening

headspace

Scroll Compressor

motor

scrolls

dome

suction opening

discharge opening

Scroll Compressor stationary scroll

driven scroll

intake

discharge

intake

discharge port

motor shaft

Scroll Compressor

journal bearing

motor shaft

driven scroll

direction of rotation

Scroll Compressor

discharge port

intake

intake

Scroll Compressor

intake phase

compression phase

discharge phase

Helical-Rotary Compressor

motor rotors

slide valve

suction opening

discharge opening

Helical-Rotary Compressor

male rotor

female rotor

housing

Helical-Rotary (Screw) Compressor

Helical-Rotary Compressor

pocket of refrigerant vapor

intake port

Helical-Rotary Compressor

meshing point discharge port

Oil Separator

refrigerant vapor and oil mixture

oil return to sump

refrigerant vapor to condenser

Oil Supply System

master solenoid valve

oil tank sump

oil filter

oil separator

rotor bearings

rotor refrigerant vapor to condenser

compressor

1 2

Centrifugal Compressor

impeller

Centrifugal Compressor refrigerant enters diffuser

path through compressor

veloc

ity

static

pres

sure

refrigerant enters impeller

refrigerant enters volute

Centrifugal Compressor

motor

impeller suction

inlet vanes

Centrifugal Compressor

volute

diffuser passages

radial impeller passages

blades impeller

Motor

impellers

impeller motor

motor gear-drive

direct-drive gears

Oil Less Centrifugal Compressor

• Magnetic Bearing Style – Danfoss, Diakin, and York direct drive with VFD

• Ceramic Bearing Style – Refrigerant cooled bearings with VFD

Semihermetic Compressor

compressor crankshaft

motor

housing

piston

Hermetic Compressor

motor

housing

compressor piston

Open Compressor

compressor crankshaft

housing

Methods of Compressor Unloading

• Reciprocating • Scroll

• Helical-Rotary • Centrifugal

Cylinder Unloaders Cycle On- Off, Digital,

VFD, Ported Slide Valve, VFD,

Ported Inlet Vanes, VFD

Cylinder Unloaders

unloader valve

refrigerant vapor

discharge

unloader solenoid valve

controller

cylinder piston

Digital Scrolls Provide Continuous Modulation

• Separation Of Scroll Elements Alternately Loads And Unloads Compressor

• By Controlling Separation Times, Compressor Is Precisely Operated Between 10-100%

• Power Linearly Related To Capacity

• Precise Temperature & Humidity Control

• Ideal For Light Commercial Split, Package And Chiller Applications

Loaded State

Unloaded State

Next Gen UltraTech Modulation Part Load Operation

Full Load Operation

Bypass Ports Sealed

Suction Pressure Communicated To Lift Chamber Via 3-Way Valve (Valve Energized)

Modulation Ring Moves Down, Sealing Bypass Ports

Bypass Ports Opened

Intermediate Cavity Pressure Communicated To Lift Chamber Via Three Way Valve (Valve De-energized)

Modulation Ring Moves Up, Opening Bypass Ports

Part Load Full Load

How Variable Speed Technology Works

Benefits Of Multiples Tandems And Trios • Load Matching

Capability Via Multiple Steps Of Capacity

• Compressors Operate Together Or Individually

• Maintains High Part & Full Load Efficiency Levels

• Ideal For Commercial Splits, Rooftops And Chillers

Slide Valve

slide valve (closed)

slide valve

(open)

valve opening

to suction

full load part load

discharge port

Slide Valve

discharge port

slide valve

housing

rotors

Heli Rotor Compressor

• Unloader ports along the rotor that open back to the compressor suction to decrease the capacity

• VFDs change speed of rotors for capacity control

Inlet Vanes

inlet vanes impeller

Inlet Vanes

25

75

10 14

63

pres

sure

diffe

renc

e

capacity

90

36 51

A

unloading line

vane position (degrees)

C B

Variable Speed

variable-speed drive

Equipment Rating Standards

• Air-Conditioning, Heating & Refrigeration Institute (AHRI) – Standard 550/590–

2015: centrifugal and helical-rotary water chillers

– Standard 560–2000: absorption water chillers

Flow Rates and Temperatures

QBtu/hr = 500 × flow rate × ∆T

[ QW = 4,184 × flow rate × ∆T ]

equation for water only

ASHRAE Standard 15–2016

• Safety standard for refrigerating systems

• Mechanical equipment room – Refrigerant monitors – Alarms – Mechanical ventilation – Pressure-relief piping

ASHRAE/IESNA Standard 90.1–2016

• Energy standard – Building design and

materials – Minimum equipment

efficiencies – HVAC system design

Equipment

FL Kw/Ton - A

IPLV - A FL Kw/Ton - B

IPLV - B

W/C Cent Chiller >600

0.56 Kw/Ton

0.50 Kw/Ton

0.585 Kw/Ton

0.38 Kw/Ton

A/C Chiller >150

10.1 EER 14.0 EER N/A N/A

W/C Screw Chiller >300

0.61 Kw/Ton

0.52 Kw/Ton

0.625 Kw/Ton

0.41

Kw/Ton

Std 90.1 – 2016 Tables