variable refrigerant flow systems: technology...

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ASHRAE Winter Conference 2016

Variable Refrigerant Flow Systems:

Technology Introduction

Dermot McMorrow, CEng Peng

Sponsored byASHRAE Technical Committee 8.7

Copyright Materials

• Copyright 2016 by ASHRAE. All rights reserved.

• No part of this presentation may be reproduced without written permission from ASHRAE, nor may any part of this presentation be reproduced, stored in a retrieval system or transmitted in any form or by any means (electronic, photocopying, recording or other) without written permission from ASHRAE.

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AIA/CES Registered Provider

• ASHRAE is a Registered Provider with The American Institute of

Architects Continuing Education Systems. Credit earned on completion

of this program will be reported to CES Records for AIA members.

Certificates of Completion for non-AIA members are available on

request.

• This program is registered with the AIA/CES for continuing professional

education. As such, it does not include content that may be deemed or

construed to be an approval or endorsement by the AIA of any material

of construction or any method or manner of handling, using,

distributing, or dealing in any material or product. Questions related to

specific materials, methods, and services will be addressed at the

conclusion of this presentation.3

Learning Objectives

• Provide overview of variable refrigerant flow (VRF) system technology

• Discuss considerations for design and application of VRF systems in buildings

• Describe applicability of ASHRAE Standard 15, Safety Standard for Refrigeration Safety requirements to VRF systems

• Review application of VRF systems in Green Buildings in cold climates

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DEFINITION – What is Variable Refrigerant Flow?

ASHRAE Journal, April 2007The term “Variable Refrigerant Flow” refers to the capability of an HVAC system to control the amount of refrigerant flowing to each of the indoor units/evaporators, enabling the use of multiple evaporators of differing capacities and configurations, individualized comfort control, simultaneous heating and cooling in different zones with heat recovery from one zone to another.

AHRI Standards & Policy Committee, June 2009 Variable Refrigerant Flow (VRF) System is an engineered direct exchange (DX) multi‐

split system incorporating at least one variable capacity compressor distributing

refrigerant through a piping network to multiple indoor fan coil units each capable

of individual zone temperature control, through a zone temperature control devices

and common communications network. Variable refrigerant flow implies three or

more steps of control on common, interconnecting piping.

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Exp

ansi

on C

ycle

Enthalpy

Low psi

High psi

Typical Pressure-Enthalpy Diagram

Condensing

EvaporatingTH 22

Refrigerant in liquidand gaseous states S

ub-c

oole

d re

frig

eran

t

Superheat Differential

TH 23

Pressure

Operating Parameters6

4

Indoor Units

WCU

InverterVariable speed control

Compressor

Accumulator

Heat Exchanger

Condenser

4-Way Valve – Changeover Heating to Cooling

Variable Refrigerant Flow – Typical System Elements

Heat Rejected

COOLING MODE

Linear Expansion Valve

T1 T2

T

HEAT SINK

WATER LOOP

GROUND

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Indoor Units

WCU

InverterVariable speed control

Compressor

Accumulator

4-Way Valve – Changeover Heating to Cooling

Heat Absorbed

HEATING MODE

Linear Expansion Valve

T1 T2

T

Heat Input ThruCompression

Refrigerant Flow

HEAT SINK

WATER

GROUND

Variable Refrigerant Flow – Typical System Elements


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What is Variable Refrigerant Flow (VRF)?Compressor Speed

Heating or

Cooling Output

Lower Limit of Compressor Speed and Capacity

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VRF Technology Benefits

• Zoning Applications

• Variable Capacity

• Distributed Control

• Low Operating Sound

• Simultaneous Heating & Cooling

• Effective Energy Usage

• Quick Installation

• Low Ambient Operation

• Low Maintenance Costs10

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VRF System Types – Heat Pump

• Heats or cools (H/C) a given space• Indoor units operate in same mode of H/C

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System Types – Heat Recovery

• Provides simultaneous H/C

• Indoor units have individual control and H/C mode capabilities

• Energy is transferred from one indoor space to another through a refrigerant line

• Double heat recovery potential in water-source VRF formats

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Water-Source VRF Heat PumpHeat Recovery in Water Loop Only

Water Circuit

System A in COOLING Mode(refrigerant absorbing heat)

Heat is recovered between the WCU within the water loop

System B in HEATING Mode(refrigerant discharging heat)

PQHY Unit “A”

PQHY Unit “B”

Cooling

Cooling

Cooling

Cooling

Heating

Heating

Heating

Heating

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Two-Pipe Heat Recovery VRF System

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Three-Pipe Heat Recovery VRF SystemsParallel Configuration Hybrid Series/Parallel Configuration

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Zone Load Report – Peak Heating/Cooling

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DOE Report – Annual Hours of Heat Recovery

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VRF Applications

• High- or low-rise offices

• Educational facilities

• Healthcare facilities

• Multiple-tenant residential buildings

• Data center cooling-only applications

• Retail stores

• Hospitality centers

• Restaurants

• Banquet halls

• Hotels

• Motels

• Cultural facilities

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Zoned Comfort Control

• Zone-by-zone temperature control

• Seamless H/C switchover for decentralized systems

• Traditional unitary system standards – ASHRAE Standard62.1

• Integrates with DOAs

• Integrates with ERB

• Factors include:– Design zone air change rate

– Level of ventilation air supplied

– Degree of airflow filtration

Figure: System Design 19

Annual Operating Efficiency Characteristics

Key Performance Factors include:

• Occupancy profile

• Orientation

• Design ventilation air requirements

• Construction

• Local outdoor ambient design parameters

• Air source vs. water-source heat rejection strategies

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11

ECWT @ 50 F Nom CLG kW Output Factor Actual CLG kW Output Nom CLG Input kW Factor Actual CLG input kW CLG COP

WCU 6 T 21.3 1 21.3 3.85 0.66 2.54 8.38

WCU 8 T 26.2 1 26.2 5.61 0.66 3.70 7.08

WCU 10 T 35.2 1 35.2 7.51 0.66 4.96 7.10

WCU 12 T 42.6 1 42.6 7.94 0.66 5.24 8.13

WCU 14 T 49.6 1 49.6 9.73 0.66 6.42 7.72

WCU 16 T 56.4 1 56.4 11.55 0.66 7.62 7.40

WCU 18 T 63.3 1 63.3 13.5 0.66 8.91 7.10

WCU 20 T 70.3 1 70.3 15.47 0.66 10.21 6.89

ECWT21

Life Cycle Cost Comparison

• Installed Capital Costs

• Life Cycle Operating Costs

▫ Annual operating costs

▫ Routine maintenance costs for inspection

▫ Equipment life expectancy• 15-20 years for air source

• 20-25 years for water source

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Industry Performance StandardsAHRI Standard 1230 (for VRF systems with capacity ≤ 760,000 Btu/h)

Table: VRF Multi-split System Classifications

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VRF Outdoor Units

• Heat Pump

• Heat Pump with Heat Recovery

• Variable Speed Compressor

• Multiple Modules can be combined to operate as a higher capacity system

• Air-to-Refrigerant

• Water-to-Refrigerant

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Indoor Units• Wall-mounted

• Recessed-ceiling cassette

• Ceiling-suspended

• Floor-standing

• Ducted

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Local Controller

Central Controller

Control Communication

Controls

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Local and Remote Monitoring

• Manufacturer-specific controls protocol to communicate between outdoor units, indoor units, and available system-specific accessories

• Designer should consult:▫ Operation manual

▫ Systems and component engineering

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System Operation Factors

• Load Management

• Cooling Operation

• Heating Operation

• Heat Recovery Operation

– Two-pipe systems

– Three-pipe systems

– Multi-layer heat recovery in water-source VRF systems

• Defrost Operation

• Oil Recovery Operation

• Humidity Control


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15

Load Management

• Indoor units control capacity through an EEV or LEV

• Outdoor unit conducts load management through inverter-driven variable-speed compressor

• Alternative combo for varying capacity and variable-speed outdoor unit fans

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Cooling Operation

Outdoor Units

• Compressor(s) adjust to match total system load by varying refrigerant flow with compressor speed or capacity control

• Main driver of system efficiency

Indoor Units• Variable cooling capacities

• LEVs/EEVs are controlled to maintain a target superheat value or evaporator temp

• Temp difference ↓

(setpoint temp – zone temp)

Then superheat ↑

(vapor pipe thermistor temp –liquid pipe thermistor temp)

And vice versa

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Heating Operation

Outdoor Units• EEV/LEV electronic

expansion valve opens and closes to maintain target superheat value

• Main driver of system efficiency

Indoor Units• EEV/LEV controlled to

maintain subcooling

• Temp difference ↓

(setpoint temp – zone temp)

Then subcooling ↑

And vice versa

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Heat Recovery Operation

• Two-Pipe Systems

• Three-Pipe Systems

• Multilayer Heat Recovery in Water-Source VRF Systems

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Two-Pipe Heat Recovery Systems

In a balanced system, peak zone heating and cooling loads are equal:

1. Refrigerant gas is delivered from outdoor unit → heat recovery control unit (HRCU)

2. Subcooled refrigerant or refrigerant gas → indoor units in cooling or heating mode

3. Refrigerant vapor leaves indoor unit → HRCU

4. Vapor → outdoor unit where it is compressed

5. Cycle repeats

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Three-Pipe Heat Recovery Systems

• HRCU controls direction of refrigerant flow through indoor units

• In cooling mode, indoor unit is an evaporator

Low pressure vapor pipe OPENS

High pressure vapor pipe CLOSES

• In heating mode, indoor unit is a zoned condenser

Low pressure vapor pipe CLOSES

High pressure vapor pipe OPENS

• Ports ≤ 634

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Multi-layer Heat Recovery in Water-Source VRF

2 levels of heat recovery:– Heat energy exchanged between zones

at refrigerant level

– Heat energy exchanged between systems through water loop

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Defrost Operation

Systems that require heating operation to shut off:

– Reverse refrigerant flow

– Outdoor unit coil becomes a condenser to melt frost

– Indoor units switch off

Systems that do not require heating operation to shut off:

– Split-coil configuration in outdoor unit(s) defrosts only half the coil at a time,

– Defrost each outdoor unit separately, or

– Defrost outdoor units on a single system together

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Oil Recovery Management

• Manufacturers may include oil separator for each compressor in system

• To reclaim small amount of oil that settles in system:▫ Controls open EEV/LEV in all indoor units after a set

period of compressor operation

▫ Compressor switches to a predetermined speed to ensure oil in system flushes back to the compressor sump

▫ Oil recovery cycle lasts from 3-6 min

• Included in AHRI testing if expected to occur every 2 hours or less

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Humidity Control

• Indoor unit dry mode activates when zone temp > dew-point temp

• A supplemental humidification unit can be used through the ventilation air system to▫ Humidify cool dry supply air through moist exhaust

air

▫ Send moisture from supply air to the dry exhaust air

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Design Considerations• Building orientation and layout

• New construction or retrofit applications

• Construction schedule

• Building occupancy characteristics

• Peak heating and cooling load profiles

• Integration of renewable energy sources

• Zone-specific design considerations

• Building space allocation for mechanical equipment

• Application-specific ventilation air requirements

• Local design weather conditions

• Local/remote control/monitoring requirements

• Life-cycle performance

• Green building certifications expectations

Figure: Indoor Unit Layout 39

Water-Source VRF Systems

• High annual system COP levels

• Consistent performance

• Low-or-high ambient heating or cooling

• No defrost cycles

• Multi-layer heat recovery

• Nominal capacities for entering water temp:

– Heating - 21°C

– Cooling - 29°C

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Air-Source VRF Systems

• External ambient design applications between 115 and -20°F

• High-sensible-heat-ratio cooling applications

• External ambient heating-dominant applications lower than -13°F

• Supplemental Heating Strategies to offset ambient derating at lower temperatures- Zone or Condensing Unit Side

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Low External Ambient Heating –Dominant Applications

• Four strategies:▫ Integration with supplemental heating

sources

▫ Water-source VRF systems

▫ High-heating-performance air-source VRF units

▫ Locating air-source unit in a temperate or controlled ambient environment

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Integration with SupplementalHeating Sources

• Supplemental heating components can be enabled based on:▫ Preset ambient temperature measured at

outdoor unit

▫ Zone-by-zone basis

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High-Heating PerformanceAir-Source VRF Units

• 100% nominal heating performance as low as -15°C ambient and 80% heating output at -25°C

• Strategies used to achieve above levels include:▫ Flash injection technology

▫ Staged compression cycle with intermediate economizer

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Flash Injection Technology• Flash injection

cycle only operates in heating mode

• Increased heating output at lower ambient temperatures

• Compressor speed is optimized based on the circuit load

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Staged Compression Cycle

• Alternative approach to achieving higher-temperature outputs at lower ambient conditions

• Adopts compound compression with intermediate economizers

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Generating Radiant Heating/Cooling and Domestic Hot Water

• System includes a refrigerant-water indoor heat exchange module with integrated controls

• Strategies for achieving each capability include:▫ Radiant floor or cooling/heating panel that receives

water from a refrigerant-to-water heat exchanger replaces indoor unit(s)

▫ VRF system can generate domestic hot water with leaving water temp ≤ 71°C by using a heat exchanger with a booster refrigeration cycle

▫ Refrigerant-to-water heat exchanger can be used for preheating purposes

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VRF System Design Example

1. Performing a Load-Profile Analysis

2. System Type Selection, Zoning and Potential for Heat Recovery

3. Accurately Sizing Outdoor & Indoor Units

4. Selecting Indoor Units

5. Ventilation Air Strategy

6. Refrigerant Piping

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Performing a Load-Profile Analysis

• Careful planning at the design stage

• Detailed analysis of project needs

• Building’s annual H/C load profiles are required before equipment is selected and sized

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System Type Selection, Zoningand Potential for Heat Recovery

• System selection driven by determining best balance between operating costs and capital costs per unit area.

• A complete energy analysis of the building:

– To evaluate system type(s)

– To determine most appropriate system for application

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Accurately Sizing Outdoor & Indoor Units

– Derating factor: Verifies chosen system will provide the required capacity at design temps

Factors to consider include: – Outdoor unit size: Based on actual peak

cooling or heating load

– Effect of local ambient conditions on system performance

– Connected nominal capacity of indoor units is within operating parameters of selected system

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Design Example: Outdoor Unit SizingOutdoor Unit Sizing is based on actual peak cooling or heating load, whichever is higher. Peak cooling load at 3:00pm in August = 27.5 kW

Peak heating load at 8:00pm in January = 21.7 kW

28 kW ODU should be selected:• 28 kW cooling load

• 31.7 kW heating load

Account for derate and corrected heating capacity factors:• Heating:▫Design winter ambient = –9°C, Derate factor = 0.74▫Refrigerant piping length correction factor at 37 m = 0.98▫Corrected heating capacity = 31.7 × 0.74 × 0.98 = 23 kW

• Cooling:▫Design summer ambient = 34.4°C db, Derate factor = 1.00▫Refrigerant piping length correction factor at 37 m = 0.98▫Corrected cooling capacity = 28.2 × 0.98 = 27.6 kW

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Selecting the Indoor Units

Factors to consider:– Peak cooling and heating

capacities

– Ratio of sensible to latent cooling load

– Air change rate (following ASHRAE Standard 62 criteria)

– Sound performance criteria

– Terminal unit air-side distribution and location restrictions

– Ventilation air strategy

– Any integration with supplemental heating components

Design Example: Indoor Unit Sizing• Connected nominal capacity of IDU must fall within operating parameters

of the selected system: VRF HP systems with a connected nominal capacity of up to 130% of OFU nominal capacity. Total indoor unit connected capacity = 35.8 kW Nominal outdoor unit capacity is 28 kW Therefore, 35.8 kW/28 kW = 128%

• The reception area requires other design considerations: Peak cooling load = 6.6 kW Peak heating load = 5.5 kW Air change rate = 4 ach Sound performance criteria = NC 35 Ventilation supply = 0.04 L/s

• Designer could choose a ceiling-recessed IDU with: Nominal cooling output of 7 kW Nominal heating output of 7.9 kW Sound performance rating of NC 30 Nominal airflow rate of 225 - 315 L/s 54

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System Ventilation Air Strategy

• Three main strategies:– Direct

– Integrated

– Decoupled

• Selection depends on:– Climate

– Application

– Equipment type55

Refrigerant Piping Design

• Refrigerant liquid and gas piping sizes

• System design verification based on:

– Max height and length differences

– Ratio of indoor unit to outdoor unit nominal capacity

• Equipment bill of materials/quantities

• Project numbering and product specifications

• Control and power schematics

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Local System Control

• Individual control by local controllers

• Temperature sensing at the return air or local controller

• Several indoor units can be grouped together under one local controller (shown above).

• Grouped indoor units may operate under individual control but must function in same mode

• Functions include:– Local setpoint control

– Scheduling and setback capability

– Cooling/heating/auto modes

– Fan-coil/fan speed control 57

Central System Control

• Users can monitor and optimize the operation of multiple zones, including any decentralized compatible energy recovery ventilators

• Functionality offers: – Seasonal scheduling

– Remote monitoring and diagnostics

– Ability to integrate building plans and schematics

– System energy management such as sliding temperature control, optimized start-up control, and setback capabilities 58

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Remote System Monitoring and Control

• Users can access system remotely for:– Operation

– Monitoring

– Optimization

• Access can be secured through:– Web-based access licenses

– Manufacturer-specific software tools

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Gateway Control to Integrate with Third-Party, Protocols, Devices or Systems

• VRF systems can monitor and control third-party devices through network-based control components.

• VRF systems may be integrated with building management systems (BMS) through a single-interface modulethat communicates with industry standard communication protocols.

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Safety Considerations for Refrigerants• ASHRAE Standard 15 specifies:

– Safe design, construction, installation, operation and inspection of mechanical refrigeration systems

• To successfully apply ASHRAE Standard 15 to a project requires:

– Classification and RCL of the refrigerant used

– Classification of occupancy type in which indoor unit or piping will be located

– Total amount of refrigerant used in system

– Any individual occupied zone(s) geometry and connected zones

– Methodology to calculate maximum amount of refrigerant that can be safely dispersed into a specific zone

• NFPA Standard 70 specifies:– Options available to manage smaller

spaces

• ASHRAE Standard 34 lists the most current information related to:

– Refrigerant designations, safety classifications, and refrigerant concentration limits (RCL)

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HVAC Industry Standards/Guidance• ARI 1230 Testing Standard

• ASHRAE VRF Design Guide Equipment & Systems 2012

• ASHRAE 34 2010 Safety Classification of Refrigerants

• ASHRAE 15 2010 Safety Standard

• CSA B52 2013 Refrigerant System Safety Standard

• CSA 22.2 No. 236 Product Safety Standard

• ASTM B280 Refrigerant Piping/Tubing Standard

• ASME 31.5 Refrigerant Piping/Tubing Standard

• ASME 16.22 Refrigerant System Component Standard

• NATIONAL & PROVINCIAL Building Codes62

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No CRN Numbers, Refrigerant Relief Valves

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Refrigerant Pipework Design and Installation Guidelines

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Refrigerant Pipework Design and Installation Guidelines

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Determining the Space Volume for Refrigerant Dilution?

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Classification of Refrigerants – ASHRAE 34 & CSA B52

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Classification of Systems – ASHRAE 15 & CSA B52

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Establishing the Impact of Building Occupancy Type on Code RCL Requirements

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ASHRAE 34 Standard – Refrigerant Concentrations

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CODE – Refrigerant Concentrations

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Why Do the RCL Values Sometimes Differ from Those in ASHRAE 34?

The value listed in CSA B52 Table 1 references the allowed % volume of refrigerantwhich is equivalent to 69,100 ppm/v (6.9% vol.) of refrigerant. This is the value used in calculating RCL when a building is located at 1500 m (or higher) above sea level taking into account for the adjustments in air density and associated impact on oxygen levels.

The value listed in ASHRAE 34 Table 1 references the allowed % volume of refrigerantwhich is equivalent to 140,100 ppm/v (14% vol.) of refrigerant. This is the value used in calculating RCL when a building is located at sea level. The adjustment factor for RCL considering ODL and ATEL. For a location @ 100 m above sea level RCL = 25.78 lbs/1000 ft3

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Location Altitude, m ATEL, kg/m3 ODL, kg/m3 R-410 A RCL,lbs/1000 ft3

Halifax 145 m 0.4155 0.4163 25.90

Quebec City 98 m 0.4131 0.4163 25.78

Montreal 233 m 0.4086 0.4163 25.50

Ottawa 70 m 0.4140 0.4163 25.84

Toronto 105 m 0.4128 0.4163 25.77

Winnipeg 238 m 0.4085 0.4163 25.55

Saskatoon 481 m 0.4004 0.4163 25.24

Calgary 1084 m 0.3805 0.3331 20.79

Edmonton 671 m 0.3941 0.4163 24.60

Vancouver 152 m 0.4113 0.4163 25.67

Refrigerant Concentration Levels – Evaluating R‐410 A ‐ ATEL & ODL

The lowest value of ATEL vs. ODL must be applied in each case

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Confirming if the System Meets the RCL Levels?Commercial Office/Location Toronto/Consulting Table 1/ASHRAE 34 – RCL = 26 lbs

IU

1000 ft3 1000 ft3 1000 ft3

Smallest Occupied Space - Dilution Volume =

1000 ft3

IUIU

IU

CU10 T

IU IU IU IU IU

Total System Charge = 22 lbs

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What if the Refrigerant Concentration Exceeds the Code Levels?1. Reduce the system refrigerant volume – Decentralize Condensing Units/System

IU

CU10T

IU IU IU IU IU

IU IU IU IU IU IU

CU5T

CU5T

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What if the Refrigerant Concentration Exceeds the Code Levels?1. Reduce the system refrigerant volume – Re-evaluate VRF System Selection

- Heat Recovery vs. Heat Pump VRF System

N

S

Heat Pump System # 1

Heat Pump System # 2

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What if the Refrigerant Concentration Exceeds the Code Levels?2. Increase the refrigerant dilution volume – Re-evaluate System Zoning

IU

1000 ft3 1000 ft3 1000 ft3

Connecting Spaces - Total Dilution Volume = 3000 ft3

Code Table 1 Note (c) ‘When the air duct system serves several enclosed spaces, the permissible quantity of refrigerantin the system shall not exceed the amount determined by using the total volume of those spacesin which the airflow cannot be reduced to less than one-quarter of its maximum when the fan is operating.’

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What Next if the Refrigerant Concentration Exceeds the RCL Levels?2. Increase the refrigerant dilution volume – Re-evaluate Dilution Transfer Openings

ISO/FDIS 519-36.3.2 Dilution transfer openings for natural convection

Dilution Transfer Area Opening = 0.0032 x M/(QLMV * V)

where,

A = required opening area, m2

M = refrigerant charge, kgV = room volume, m3

QLMV = RCL is the maximum refrigerant concentration for the space, kg/m3

ASHRAE 15-2010 7.3.1 Non-connecting Spaces

‘Where a refrigerating system or part of therefore is located in one or more enclosedoccupied spaces that do not connect through permanent openings or HVAC ducts, the volume of the smallest occupied space shall be used to determine the refrigerant quantity limit in the system.’

The Japanese Refrigeration Standard [JRA-GL13] defines a permanent opening as one that has an area of 0.15% or more of the total floor area of the smaller enclosed occupied space in which refrigerant-containing parts are located.

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System Expansion for Future Reconfiguration

• During design phase, designer and client can discuss any possible future or changing needs within the building envelope

• Easy system expansion or reconfiguration as building needs change, like:▫ Upsizing VRF outdoor units to anticipate supplementary

indoor units

▫ Indoor units can be added to the VRF system

▫ Indoor units can be exchanged for different models or capacities

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Optimizing VRF Systems Minimize Environmental Impact

• Part-load capabilities, modular design, zoned approach, heat recovery operation, and use of VFD compressors provide comfort while consuming less energy

• Factors that increase efficiency:

– Correct sizing

– System control

– Proper maintenance

– Correct installation

– Maximizing heat recovery potential

– Zone control and energy performance optimization

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What Constitutes Good HVAC System Design Practice???

Good Design = Sustainable Design?

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What is Sustainable Design?‘Sustainable design is defined as creating a product (building) that has maximum impact for our client but has minimum impact on the earth or its resources, both now and in the future.’

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What is the Fundamental Requirementof an HVAC System in a Building?

‘Provide the desired environmentto realize occupant comfort’

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What Environmental Conditions Facilitate Human Comfort?

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Comfort Goals 1. Space Temperature2. Space Humidity3. Air Motion4. Air Quality5. Air Changes per Hour6. Air and/or water velocity requirements7. Local Climate8. Space Pressure Requirements9. Capacity requirements from a load calculation analysis10. Redundancy 11. Spatial requirements12. Security Concerns13. First Cost14. Operating Cost including energy and power costs15. Maintenance Cost16. Reliability17. Flexibility18. Controllability19. Life Cycle Analysis 20. Sustainability of design21. Acoustics and Vibration22. Mold & mildew prevention

Additional Goals1. Increasing marketability of rental spaces2. Increasing net rental income3. Increasing property salability4. Public Image of Property.

2012 ASHRAE Handbook‐

HVAC Systems & Equipment

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Complete Building Integration with the Environment

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Where Do I Start and Where Do I Finish?

Five key strategies for optimizing the performance of building systems: 1. Where feasible, reduce the total output or the duty seen by the system.

2. Make use of available environmental resources (thermal for HVAC systems).

3. Optimize the efficiency of the individual components of the system.

4. Accurate system control and functional coordination of the components.

5. Where possible, offset system energy input with renewable energy sources.

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What are the hierarchy of building elementsthat must be considered during the design process?

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Building: Two Story, LEED Platinum 36,000 ft2 Office BuildingOwner: Upper Thames Regional Conservation AuthorityLocation: London, Ontario Design Data: Winter/Summer – 160C/ + 300C

Building Name: Water‐shed Conservation Centre

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Solar Wall Technology Tempering Ventilation Air

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Solar Wall and Earth Tube Layout

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Solar Wall Installation

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Solar Wall Installation

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AUGUST DATA- ENERMODAL ENGINEERING

FEBRUARY DATA- ENERMODAL ENGINEERING

Ventilation Air Preheat/Cool via Earth TubeWINTER: UP TO 20OF TEMPERATURE RISESUMMER: UP TO 6OF TEMPERATURE DROP

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STORAGE CLASSROOM

MEETINGOFFICEOFFICE

OUTSIDE AIR (OA)-VENTILATION AIR

SUPPLY AIR

RETURN AIR

AHU

10% OA 40% OA

30% OA15% OA15% OA

35% OA

PROBLEM: YOU END UP OVER-VENTILATING MOST SPACES

ASHRAE Std 62.1

AHU IS USED FOR:1. Heating2. Cooling3. Ventilating

T

Ventilation System Design Concept

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STORAGE CLASSROOM

MEETINGOFFICEOFFICE

OUTSIDE AIR (OA)-VENTILATION AIR

SUPPLYAIRAHU

10% OA 40% OA

30% OA15% OA15% OA

ASHRAE 62.1: OUTSIDE AIR IS A FUNCTION OF AREA AND NUMBER OF PEOPLE IN SPACEDEMAND CONTROL VENTILATION

100% OA

AHU IS USED FOR:Ventilating only

Heating and cooling is done through dedicated zonal units

CO2

OO CO2

H/C

VFD ON SUPPLY FAN

T

Ventilation System Design Concept

101

Ventilation System Design

102

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Ventilation System Design – DOAS Unit

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104

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105


106

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108

Variable Refrigerant Flow Condensing Units

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Variable Refrigerant Flow Piping Schematic

Heat Pump

Compressor Energy1 kW

Low Temperature RenewableHeat Recovered from the Air

High TemperatureHeat Output to Space

5 kW

Heat Pump

Compressor Energy1 kW

Heat rejected to Outside Ambient

Space Cooling Input 5 kW

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Variable Refrigerant Flow System Piping Layout

110

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Variable Refrigerant Flow System Layout – BC Controller Installation

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Variable Refrigerant Flow System Layout – Ducted Indoor Units

112

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Variable Refrigerant Flow System Layout – Ducted Indoor Units

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Variable Refrigerant Flow System Layout – Cassette Style Units

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116

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SUMMERWINTER

Domestic Hot Water Heating

SPRING, AUTUMN SPRING, AUTUMN

Variable Refrigerant Flow System Layout –Heat Recovery Potential

TANK

Bathroom

Shower

Sanitary equipment

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Pump Water

LEV

Booster Unit

Comp.R134

a

CONDENSING

UNIT

BC controller

Indoor unit

Indoor unit

R410A

Up to 2.15 m3/h or 9.46 gpm

T_water_outlet+5degC(9F)75 (167F)

(160F)

40 (104F)

50 (122F)

65 (149F)

Closed loop circuit

Treat the water with additive

TANK

Bathroom

Shower

Sanitary equipment

Heat recovery

Cooling

Variable Refrigerant Flow System Layout – Heat Recovery Potential

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Building Energy Analysis & Performance

Additional Capital Cost 160,000 $Savings per Year 33,726 $Payback Period 4.74 Years

The latest field measurements indicate annual energy usage 61.6 kwh/m2/yearHVAC System = 26-28 kwh/m2/yr

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Questions/Conclusion

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Evaluation and Certificate

• ASHRAE values your comments about this course. You will receive your Certificate of Attendance when you complete the online course evaluation at this URL: http://ali.ashrae.biz/2016winterconferenceAccess code: d4c2 Be sure to add your appropriate license numbers.

• If you have any questions about ASHRAE Certificates, please contact Kelly Arnold at [email protected]

• If you have any questions about ASHRAE courses, please contact Martin Kraft, Managing Editor, at [email protected]

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ASHRAE Career EnhancementCurriculum Program

Expand your knowledge of IAQ and Energy Savings Practices through a select series of ASHRAE Learning Institute courses

• Receive up-to-date instruction on new technology from industry experts

• Gain valuable HVAC knowledge

• Accelerate your career growth

• Receive a certificate for successful completion of the course series

Visit www.ashrae.org/careerpath to learn more.

ASHRAE Professional Certification• Do you want to stand out from the crowd? Become ASHRAE

certified. ASHRAE certification serves as a springboard for your continued professional development.

• Assure employers and clients that you have mastered the body of knowledge that subject matter experts have identified as reflecting best practices.

• Please visit the following URL to learn more about our programs: www.ashrae.org/certification▫ Building Energy Assessment Professional

▫ Building Energy Modeling Professional

▫ Commissioning Process Management Professional

▫ Healthcare Facility Design Professional

▫ High-Performance Building Design Professional

▫ Operations & Performance Management Professional126

variable refrigerant flow systems: technology...

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