Boilers and Chillers and Savings…Oh My!...ASHRAE 90.1-2016 ≥15 Not addressed ASHRAE GreenGuide...

Boilers and Chillers and Savings…Oh My!

John Smart, Weil-McLain

Mike Molnar, Trane

Scott Lucykow, Trane

John Smart, Weil-McLain

The Modern Hydronic System

Energy Savings Made Easy | 2019 Business Symposium

Boiler Replacement

»Is it time to replace your boiler?

»A simple question

» What is the age of your existing system?

» How much energy do you use to heat your building?

» How much money do you spend maintaining your system?


What are my options

»Standard Efficiency Products• Usually the lowest priced option

• Older technology

• Lower Efficiency

− 80%


Boiler Replacement

»High Efficiency Products

» Higher priced option

» Reduced energy consumption

» High system Efficiency

» How much money do you spend maintaining your system?

» Incentive dollars available


Boiler Replacement

»A real look at efficiency


Outdoor Reset / Set Point

2008 ASHRAE Handbook

8%


%o

f Lo

ad

100

13 days = 5% of

the season

37 days = 14% of

the season

83 days = 30% of the

season

72 days = 26%

of the season

68 days = 25%

of the season

Based on the 1990-1991 heating season 273 days

total in Southeast Wisconsin

-10º

F

10º F0º F 50º F28º F

65º F

0

A Real Look at Efficiency

50


Boiler Replacement

Scott Lucykow & Mike Molnar, Trane

Chiller Energy Advancements


Agenda

» Chiller design changes

• Refrigerant changes

• Component improvements

− Heat Exchangers/Coils

− Compressors

− Controllers

• Code changes

» System Design and Control Strategies

» Heat recovery and Free cooling resurgence

» Thermal Storage

» MyPLV quick analysis tool

Chiller Design Changes


Choices & Comparison

Screw & Centrifugal Technology Options

Chiller efficiency impacted by refrigerant choice – growing customer optionsCONFIDENTIAL AND PROPRIETARY INFORMATION OF TRANE & Ingersoll-Rand

Next-GenTransitionalCurrent


Sustainability

Environmental Stewardship• Low global warming potential refrigerant

• Operates with either R-134a or R-513A

• DuPont’s Opteon® XP-10 (R-513A)

• 55% reduction in GWP vs. R-134a


Types of Compressors

15

helical-rotary (screw)

centrifugal

scroll


Overview

» Scroll Compressor Modulation Methods

• Single ON/OFF Compressor

• Dual or Manifolded ON/OFF Compressors

• Digital

• Variable Speed Drive

• Intermediate Discharge Valve


Single On/Off Compressor

» Capacity modulated by turning compressor on/off

» Very simple control system

» Greater stress on electrical and mechanical system from

starting torque and current due to frequent startups

EfficiencyFull load

EfficiencyIPLV

Temperature Control

ControlComplexity

Cost

Best Poor Poor Low Low


Digital Scroll

» A digital scroll operates in two stages - loaded & unloaded (0% to

100%) by increasing the tip gap to prevent compression

» An actuator pushes the top scroll into and away from the orbiting

scroll to switch from load/unload

» This system is more complex

» Compressor continues to draw power in an unloaded state

» Digital scrolls are much louder than conventional scroll

EfficiencyFull load

EfficiencyIPLV

Temperature Control

ControlComplexity

Cost

Good Good Best High High


Variable Speed Scroll

» A variable scroll modulates capacity by varying the speed of the

compressor motor.

» Motor speed is controlled by the drive frequency and speed is

reduced for lower capacities

» Proper bearing oil flow at low speeds is a concern

» This requires complicated controls and additional losses from the

motor driver

» This does allow for precise temperature control

EfficiencyFull load

EfficiencyIPLV

Temperature Control

ControlComplexity

Cost

Poor Best Best High High


Efficiency

Optimized for part load efficiency

• Scroll compressors with Intermediate

Discharge Valves (IDVs) to optimize

energy use at all load points

• EC fan motors eliminates losses due to slip

resulting in 2-4 % higher efficiency.

IDV Scroll Compressor


Comparison Summary

CompressorTechnology

EfficiencyFull load

EfficiencyIPLV

Temperature Control

ControlComplexity

Cost

Single On/Off Best Poor Poor Low Low

Manifolded On/Off Best Good Good Low Medium

Digital Good Good Best High High

Variable Speed Poor Best Best High High

Intermediate Discharge Valve

Best Best Good Low Medium


Variable Volume Ratio Screw Compressor

Variable volume ratio compressor is

optimized for variable operation

delivering peak efficiency under all

operating conditions

Variable volume ratio eliminates losses

due to over or under compression.

Efficiency


Permanent Magnet

motor eliminates

losses due to slip

resulting in 2-4 %

higher efficiency.

EfficiencyInduction

Motor

Permanent Magnet

Motor

Rotational SlipInduction motor “slips” in order to establish a

magnetic field in the rotor to produce torque.

The power in the rotor is lost as heat. As

more torque is required, more slip occurs.

No Rotational SlipPermanent magnet motor has its rotor magnetic

field permanently provided by the magnets. No

external power is necessary as in the induction

motor.

Permanent Magnet Motor


Low-Charge Evaporator

CHIL™ evaporator - Compact, High-efficiency,

Integrated, Low-charge

»Suction Distributor design allows for higher velocity

• Reduces total refrigerant charge by up to 25%

• Reduces evaporator footprint by up to 25%

• Improves efficiency over traditional falling film or flooded designs

• Reduces carryover for increased reliability

ACR providing premium efficiency

Efficiency


MicroChannel Condenser Coils

MicroChannel Condenser Coils

» Extremely efficient

» All aluminum coils reduce potential for corrosion

» Coils are lighter than traditional fin and tube coils

» Less refrigerant in the system

» Fewer opportunity for leaks, elimination of braze joints

» More robust for cleaning

Reliability


lvg evaporator water

lvg condenser water

gpm = 1725

load = 1150 tons

lift (∆T)

61.9ºF

Chiller Basics – Load and Lift

lift = Pcnd – Pevp

lift ∝ Tlvg cnd – Tlvg evp

kW ∝ load × lift

“Series-Series Counterflow for Central Chilled Water Plants,”

ASHRAE Journal, June 2002.


Magnetic Bearing Centrifugal Compressor (Water Cooled)

Robust Compressor Design

• Multi-stage, Direct drive

• Magnetic Bearings

• Speed optimized for refrigerant

• Balance thrust design

• Wide-operating map, high-lift

• Permanent magnet motor

• Oil-free design

Multi-Stage provides stable operation over a wider

operating map delivering efficiency AND reliability

RP

M

Tons

Med Pressure

Low Pressure

Specific Speed delivers optimized performance

500 1000100

15k

5k

35k

25k


Key Features

C Refrigerant Cooled

Drive

AAdaptiView™

Controller

BHarmonic Filtration (5%

TDD)

D24 Pulse AFD3

ETube & Clips

F Low Pressure Refrigerant

Complete Chiller

GOil-Free

CONFIDENTIAL AND PROPRIETARY INFORMATION OF TRANE

Oil Free Ceramic Bearing Centrifugal Chiller


• Mixed Flow Impeller

• Specific-Speed

• Permanent Magnet Motor

• Balanced Impeller Configuration

• Direct Drive

• Multi-Stage

• Low Pressure R-123 Refrigerant

Compressor Design

Design Requirements

1. industry leading unit efficiency(Small tonnage range)

Full load Part load

2. Provide a comprehensive operating map to meet system needs

High lift Low lift Flexible

CO

NFI

DEN

TIA

L A

ND

PR

OP

RIE

TAR

Y IN

FOR

MA

TIO

N O

F TR

AN

E

Efficiency Drivers


HeatExchangers

Motor & Drive train

Control Power & VFD Bearings

Base Design

Elements

to Chiller

EfficiencyEconomizer

Multi-Stage

Direct Drive

Sub-Cooler

PM Motor

Impeller Design

Unit Efficiency is Dependent on a Number of Design Elements

Compressor Aerodynamics

Refrigerant

Efficiency Boost

+4%

+6%

+2%

+2%

+3%

+6%

As compared to a simple cycleActual values will vary based on chiller construction

Design Choice Impacts

System Design and Control Strategies


Direct Digital Controls

» On board Chiller controls allow precise controls of high technology chiller components.

» Front end system controls allow complex energy saving strategies to be implemented with the click of a button


Theory 4: 10 Degree ∆T “Started” With Well Water

• March 2, 1935“Well water jobs can be estimated in the

usual manner by allowing about a

10 degree rise in the well water temperature….

…This job on which Trane coils were used

and guaranteed to maintain an 80 degree

dry bulb temperature and a 50% relative

humidity with an outside air temperature of

95 degrees.”


It’s Time to Listen to the Industry……and Provide Better System Designs

Source Chilled Water ∆T Condenser Water ∆T

ºF ºF

ASHRAE 90.1-2016 ≥15 Not addressed

ASHRAE GreenGuide 12 – 20 12 - 18

50% AEDGs

Small/Med office

K-12 Schools

Hospitals

≥15

12 – 20

≥15

(air-cooled)

Not addressed

≥14

Taylor (ASHRAE Journal) >12 15

ASHRAE Learning Institute ChW

Course

Begin with 25! Begin with 15


Why Higher ∆T Recommendations are Being Made

3.003.504.004.505.005.506.006.507.007.50

Fu

ll L

oad

CO

P

Required Full Load COP

200 Ton Positive

200 Ton Centrifugal

500 Ton Centrifugal

Chiller Type Efficiency Increase

200T Positive 67%

200T Centrifugal 52%

500T Centrifugal 65%

A History of Chiller Performance


Pump Pressure Optimization

Air Handling Units

control valves

with communicating

controllers

communicating BAS

pressure

differential controller

/transmitter


Chiller-Tower Interaction

Wet bulb

Condenser watertemperature

Load

Tower design

Load

Condenser watertemperature

Chiller design


Condenser Water Control

“Normal” Set Point

» Hot?

e.g., 85°F, minimizes tower energy consumption

» Cold?

e.g., 55°F, minimizes chiller energy consumption

» Optimized?


Optimal Condenser Water Control Chiller–Tower Interaction

condenser water temperature, °F

400

74

en

erg

y c

on

su

mp

tio

n, kW

76 78 80 8272

300

200

100

084

tower

chiller

total

optimalcontrol point


Lesson

Work the most efficient system component (the chiller)…

…a little harder


Convert Primary Secondary to Variable Primary

Variable Secondary

Placeholder for

Manifolded P-S

System picture

(Beth to supply)

VFDs

T

DP

DP


Convert Constant Flow to VPF

1. Check unit controller for VPF compatibility

2. Add VSD to pump

3. Change some 3-way valves to 2-way

4. Leave enough 3-way valves to allow minimum flow

5. Control pump VSD to maintain minimum flow

12

4

3

5

DP

Can also be applied to new, single-

chiller systems


Series Chillers

Heat Recovery, Free Cooling, & Thermal Storage


Heat Recovery

How does it work?

» Supplemental BPHE installed on compressor

discharge line

» Produces up to 158ºF leaving water temperature

» Roughly 15 - 20% of heat recovered from cooling

load

» Simultaneously produce chilled and hot water

» Factory installed and tested

» Compressor discharge temperature and fan-speed

control

What is it?

Recovering heat from a chiller, rather than simply rejecting it.

Heat Recovery


System Configurations

Variable Primary Flow

VFDmodulating control valvefor minimum chiller flow

Piping heat-recovery chiller

in sidestream position

simplifies control

controlvalve

bypass line

heat-recoverychiller


Free Cooling

Ideal Applications

» Regions with year round cooling load and low ambient temperatures.

» Relatively warm chilled fluid.

» Requirement to use a water-side economizer rather than an air-side economizer.

» Factory installed and commissioned

» Compact footprint

» ROI tool in TOPSS to calculate financial

payback

What is it?

Fluid cooler integrated into the footprint of an Air-Cooled chiller

Free Cooling

» A great fit for…• Sensible loads• Continuous Cooling• Data Centers• Process Applications• High leaving chilled water temps• Cold climates

» The advantage of chiller integrated free-cooling is the ability to utilize outdoor air temperatures to assist in making chilled water when appropriate.


Free Cooling

» Up to 100% of the nominal capacity for lower energy use and added

redundancy

» Onboard free cooling has a smaller footprint than systems with a

separate dry cooler

» Simple, reliable and integrated system controls

» Free cooling ‘dry cooler’ coils upstream of condenser microchannel

» A set of valves re-directs flow through free cooling coils then to the

evaporator when operational

» Requires freeze inhibitor in chilled water loop


Thermal Storage

Why Thermal Storage?

» Lower kWh consumption

» Lower peak kW

» Lower first cost and operating cost

» No water consumption

Advantage

» Increases speed of installation

» Prepackaged control is a key to success

» Proven variable primary flow sequences

» Arrives wired and programmed

» Factory startup support

Ice made easy

What is it?

Thermal energy storage stores energy for later use,

like a battery. Thermal energy storage builds and

stores ice in modular tanks during the electrical

load’s off-peak hours for use the following day

Thermal Storage


Thermal/Ice Storage Benefit Summary

Lower utility costs

• Lower on-peak electrical consumption (kWh)

• Lower on-peak electrical demand (kW)

Smaller equipment size

• Smaller chiller

• Smaller electrical service (A)

Reduced installed cost

• May qualify for utility rebates or other incentives

50


Ice Bank® Thermal Energy Storage

Industry Leading Design and Operation

» Near zero maintenance

» Extremely durable

» Long-life with the industry’s best warranty

» Can be partially or fully buried


Small Air-Cooled System

52

coolingcoil withthree-waycontrol valve

bypassvalve pump

icevalve

air-cooledchiller

ice storagetanks


Modes of Operation

53

0

25

50

75

co

olin

g l

oa

d,

% o

f d

es

ign

100

midnight 6 a.m. noon 6 p.m. midnight

chiller

only

ice

only

chiller

and

ice

freezefreeze



Understanding the impact of unit performance on your electrical bill

• “Demand” (kW)- rate of electricity used

• “Energy” (kWh)- quantity of electricity used

• Other charges- ratchets rates- time of use- seasonal (winter & summer)

Total Cost of Ownership

Where is money spent over the chiller’s lifetime?

Life-time Investment

Cost

First Cost (5%)Service (6%)

Electricity (89%)ACR Exceeds ASHRAE 90.1-2016 Path B

full load by 18% and IPLV by 22%


MyPLV Comparison Tool


Defining Life Cycle Value

Accurate Performance Based on Specific Application

• Performance value calculated based on specific project

• Installation location• Building type• Operation conditions• Chiller plant design

• Excel based

• Industry validated data

• Vendor agnostic

myPLV®

Life Cycle Cost Analysis

myPLV®



Where’s the Meter?

On the

BUILDING


Questions ?

Date post:	06-Jul-2020
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Boilers and Chillers and Savings…Oh My!...ASHRAE 90.1-2016 ≥15 Not addressed ASHRAE GreenGuide...

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