Technical Development Program COMMERCIAL HVAC PACKAGED EQUIPMENT Split Systems PRESENTED BY: Ray Chow Sigler
Menu Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Section 7 Introduction System Basics System Components Accessories Controls Installation Summary
SECTION 1 SPLIT SYSTEMS Introduction
Objectives Identify applications that utilize the strengths of split systems Identify the components of split systems Understand the impact codes have on system application and selection Compare the differences in outdoor and indoor unit types Understand key installation issues Section 1 Introduction
Split Systems Components Condensing Unit Indoor Unit AHU (Fan Coil) Indoor Unit Furnace And Coil Section 1 Introduction
Split Systems Residential to large commercial ¾ to 120+ tons Applications Cooling only Cooling with heat Heat pump Furnace with coil Utilize packaged products in an applied manner Section 1 Introduction
ARI System Classification Single Package Remote Condenser Year Round Remote Condenser Condensing Unit with Coil Fan Evap Comp Cond Fan Evap Comp + Cond Fan Evap Heat Comp + Cond Evap + Cond Comp Condensing Unit with Coil + Fan Fan Evap + Cond Comp Year Round Condensing Unit with Coil + Fan Fan Evap Heat + Cond Comp Split Systems 5 ARI cooling split system categories ARI has categories for air, evaporative or water-cooled Plus 4 ARI heat pump categories (not shown) Section 1 Introduction
SECTION 2 SPLIT SYSTEMS System Basics
Split System Basics Indoor Unit Outdoor Unit Liquid Line Warm-Temp., High-Pressure Liquid Filter Drier Suction Line Low-Temp., Low-Pressure Vapor Sight Glass Liquid Line Solenoid Valve Section 2 System Basics
Why Use a Split System? Flexibility Aesthetics Duct design Performance Zoning Section 2 System Basics
Flexibility Mix and match indoor and outdoor units Closely match load requirements Use only manufacturer s approved combinations 10-ton AHU OR 10-ton condensing unit 12½-ton AHU Section 2 System Basics
Residential & Duct Free Systems Section 2 System Basics
Condensing units include: Controls Condensing Units Compressors Condenser Coil Section 2 System Basics
Typical Condensing Units Section 2 System Basics
Typical Indoor Unit Cased Evaporator Coils Packaged AHU Central Station AHU Section 2 System Basics
Heat Pump System Indoor Unit Evaporator in cooling Condenser in heating Outdoor Unit Condenser in cooling Evaporator in heating Section 2 System Basics
Refrigerant Circuits Single Circuit Dual Circuit Section 2 System Basics
Indoor Unit Refrigerant Circuits Single Circuit Distributor Dual Circuit Solenoid TXV LIQUID LINE LIQUID LINE TXV Filter Drier Distributor Section 2 System Basics
ARI Standards Standard # 210/240 Applies to Unitary Air Conditioners Air Source Unitary Heat Pumps (Air-Cooled) Capacity Range <65,000 Btuh <65,000 Btuh 340/360 Unitary Air Conditioners Air Source Unitary Heat Pumps (Air-Cooled) 65,000 to <250,000 Btuh 65,000 to <250,000 Btuh 365 Air Conditioning Condensing Units >135,000 to <250,000 Btuh Section 2 System Basics
EER EER = EER EER EER Capacity( Btuh) Total Power Input( Watts) Example 25-ton condensing unit @ ARI conditions EER = = Capacity(Btuh) Total Power Input (Watts) (22.8 290 = 25.9 = 11.2 290 MBtuh + 3.1) kw Section 2 System Basics
Net vs. Gross Capacity System EER = Net Capacity Total Power (Btuh) Input Net Capacity = Gross Capacity - IFM Heat Section 2 System Basics
BHP Required AHU Size Airflow cfm External Static Pressure (in. wg) 0.0 0.2 0.4 0.6 rpm bhp rpm bhp rpm bhp rpm bhp 028 10,000 615 3.12 641 3.36 692 3.87 743 4.41 Interpolate to derive bhp for 0.44 in. wg bhp @ 0.44 in. wg = 4.00 bhp Section 2 System Basics
IFM Heat IFM Heat = (bhp * 746) Motor Efficiency IFM Heat = (4.00 * 746) 0.83 IFM Heat = 3,595 Watts 3,595 Watts * 3.414 Btuh Watts = 12,274 Btuh Section 2 System Basics
Net Capacity Net Capacity = Gross Capacity IFM Heat Net Capacity = 294 IFM Heat Net Capacity = 282 MBtuh Section 2 System Basics
Total Power Input OFM power per motor = ( bhp * 746) Motor Efficiency Now calculate Total Power Input using data from previous slides Total Power Input = Compressor power + IFM power + ODF power Total Total Power Power Input Input = = 22.8 29.5 kw kw + 3.6 kw + 3.1 kw Section 2 System Basics
System EER System EER for the 25-ton example system: System EER System EER System EER = = = Net Cooling Capacity Total Power Input 282 MBtuh 29.5 kw 9.6 Section 2 System Basics
SEER Applies to: Single phase power only Capacity less than 60 MBtuh Calculated at three conditions and cycle test: 80/67 F return air, 95 F outdoor air 80/67 F return air, 82 F outdoor air 80/57 F return air, 82 F outdoor air 80/57 F cycle test, 82 F outdoor air Requires laboratory testing and is not calculated in the field. Section 2 System Basics
IPLV FOR ALL 3 Æ AND WATER-COOLED UNITS AND AIR-COOLED UNITS ABOVE 60 MBH CAPACITY Evaluate equipment efficiency at less than full capacity Applicable only to equipment with more than one stage of capacity Weighted average of EER at each capacity step PART LOAD FACTOR CURVE Equipment with greater number of capacity steps can more closely match the load requirements of the space Unless equipment is always operated at 100% capacity, a higher IPLV is preferred Section 2 System Basics
Coefficient of Performance Applies to heat pumps that operate on 3-phase power only Measures efficiency while operating in the heating mode A higher COP indicates a more efficient heat pump COP = Net Capacity ( Watts) Total Power Input ( Watts) Section 2 System Basics
Heating Seasonal Performance Factor HSPF: Applies to heat pumps that operate on single phase power and have a cooling capacity of < 5.5 tons only Is similar to SEER in that it measures the seasonally adjusted efficiency of a heat pump Accounts for defrost and required electric heat A higher HSPF is a more efficient heat pump Section 2 System Basics
Energy Codes Many codes rely on ASHRAE 90.1 that sets minimum efficiency requirements. Air-Cooled Split System Requirements Performance requirements < 65,000 Btuh 10.0 SEER 1Ø 65,000 < 135,000 Btuh 10.3 EER 135,000 < 240,000 Btuh 9.7 EER 240,000 < 760,000 Btuh 9.5 EER / 9.7 IPLV 760,000 Btuh 9.2 EER / 9.4 IPLV Control requirements Motor hp limits Economizer requirements Heat pump requirements Section 2 System Basics
IAQ and Sustainability IAQ ASHRAE 62 Limits maximum humidity to less than 65% Indoor unit condensate control Indoor unit ventilation capability Sustainable Design LEED Require meeting ASHRAE 90.1 efficiency and ASHRAE 62 IAQ features Optimized energy performance and IAQ Split System mix and matches provide better humidity control and flexibility to meet these requirements Section 2 System Basics
SECTION 3 SPLIT SYSTEMS System Components
Rules of Thumb Rules of Thumb are considered to be guidelines only Airflow: - 400 cfm per nominal ton - Range of 300 to 500 cfm per ton - Today, 350 cfm per ton may be more appropriate Mix and Match: - Nominal and one size up, sometimes one size down, others depend (consult the manufacturer) Line Length: - Keep them at 100 ft or less Section 3 System Components
Operating Limits Cooling only equipment: Maximum outdoor air temperature Minimum return air temperature Maximum return air temperature Saturated suction temperature range Maximum discharge superheat Minimum discharge superheat 115 F 55 F 95 F 25 to 55 F 275 F 60 F Typical saturated suction temperature range for air conditioning duty is 40 to 50 F Heat Pumps: Maximum outdoor air operating temperature in heating Minimum outdoor air operating temperature in heating 75 F 20 F Section 3 System Components
Outdoor Units Residential 1½ to 5 ton Commercial 6 to 100+ ton Duct Free ¾ to 5 ton Section 3 System Components
Semi-Hermetic Compressor Cylinder Unloader Repairable Capacity Control Section 3 System Components
Multiple Compressors Dual Scroll Dual Semi-Hermetic Reciprocating Section 3 System Components
Multiple Condensing Units Dual Circuit Indoor Unit 2 nd Stage Condensing Unit 1 st Stage Condensing Unit Section 3 System Components
Hot Gas Bypass Liquid Solenoid Valve Evaporator TXV Sight Glass Compressor Hot Gas Solenoid Valve Protects system in low load conditions Prevents coil icing Injects hot gas at indoor unit Activates at minimum step of cooling only Filter Drier Discharge Bypass Valve Condenser Section 3 System Components
Alternative Condensing Unit Solutions Triple-Split Water-Cooled Condensing Unit Condenser To indoor coil From indoor coil Compressor Section 3 System Components
Heat Pump System Check Valves TXV with bypass OUTDOOR COIL 4-Way Valve Compressor INDOOR COIL Accurator Accumulator Heating Mode Bi-flow Filter Drier Bi-flow TXV Section 3 System Components
Heat Pump System Check Valves TXV with bypass OUTDOOR COIL Filter Drier 4-Way Valve Compressor INDOOR COIL Accurator Accumulator Cooling Mode Bi-flow Filter Drier Bi-flow TXV Section 3 System Components
Indoor Unit Air Handler 6 to 30 ton Packaged AHU with limited options Central Station AHU Section 3 System Components
IAQ Features Double-Wall UV-c Lamps Double-Wall Dual-Density Insulation Foil-Face Insulation UV-c Lamps Section 3 System Components
Constant Volume AHU Variable pitch pulley is set at required airflow at first unit start-up Fan then operates at a constant speed Section 3 System Components
VAV Application VFD Inlet Guide Vanes COIL MOTOR SUPPLY FAN VAV Terminal Section 3 System Components
VAV Requirements Filter Drier Capacity Control Solenoid TXV Distributor LIQUID LINE Sight Glass Indoor Unit At least two circuits Equipped with capacity control valve(s) Section 3 System Components
VAV Requirements Outdoor Unit Multiple stages of capacity Electric control of capacity stages Suction line accumulators Interface with VAV controller Section 3 System Components
VAV Controller Typically controls discharge air temperature Controls: Compressors Stages of capacity Fans Section 3 System Components
Cased Evaporator Coils Installed in duct A coil design, installed on twinned furnaces Section 3 System Components
Residential Coils Cased Uncased Section 3 System Components
SECTION 4 SPLIT SYSTEMS Accessories
Economizer Free Cooling Outdoor air Control types Dry bulb Enthalpy Differential enthalpy CO 2 Demand controlled ventilation (DCV) Return air Section 4 Accessories
Heating Accessories Electric Heat Accessory on Packaged AHU Hot Water or Steam Coil on Packaged AHU Section 4 Accessories
Furnaces Horizontal Furnace with downstream cooling coil Twinned Furnaces Section 4 Accessories
Accessories Plenum Condensate Drain Return Air Grille Subbase Section 4 Accessories
SECTION 5 SPLIT SYSTEMS Controls
Controls - Thermostat Simple control requirements: Indoor fan Outdoor fan(s) Compressor(s) Liquid line solenoid Section 5 Controls
Two-Stage Thermostat Y1 initiates 1 st stage cooling Y2 initiates 2 nd stage cooling Section 5 Controls
Capacity Control Solenoid Valve Y1 initiates 1 st stage cooling AND opens the liquid line solenoid valve Y2 opens the liquid line solenoid valve Section 5 Controls
DDC Control User Interface Section 5 Controls
Safeties Outdoor Unit High-pressure switch Low-pressure switch Indoor Unit Motor protection Airflow switch Discharge gas thermostat Oil pressure switch Cycle protection Compressor overtemperature protection Circuit breakers Section 5 Controls
UNIT 38AR Z007 Z008 Z012 S012 COND TEMP (F) Low Ambient Control MINIMUM OUTDOOR-AIR OPERATING TEMPERATURE MINIMUM OUTDOOR TEMP (F) 80 80 80 80 80 Std. 35 35 35 35 35 D012 80 35 Proper operation of expansion device at low outdoor temps Minimum outdoor air operating temperature Maintain minimum SCT With Motormaster Control Low ambient controller OFM motor controller -20 Motormaster Control Section 5 Controls
Fan Cycling Pressure Switch Intermediate Season SCT Control Device #2 OFM Motor #1 Turn off #2 OFM motor when SCT falls too low DO NOT cycle #1 OFM motor on/off because a speed control device is required Section 5 Controls
Wind Baffles Wind baffles may be required in areas of sustained high winds, at least on the windward side. WIND BAFFLE Section 5 Controls
SECTION 6 SPLIT SYSTEMS Installation
Power Supply Minimum Circuit Ampacity (MCA) determines required wire size MCA = (1.25 * Current of largest motor) + Sum of all other loads MCA of a condensing unit = (1.25 * RLA of compressor) + (FLA of OFM motors + Control amps) MCA of indoor unit with electric heat = (1.25 * FLA of largest motor) + (1.25 * FLA of electric heater) + Sum of all other loads Section 6 Installation
MOCP Defines MAXIMUM size of overcurrent protective device A smaller device may be used, if nuisance trips are not a problem MOCP = (2.25 * Current of largest motor) + Sum of all other loads Round down to the next lower standard rating, but not lower than the MCA value Section 6 Installation
Protective Device Fuse or Circuit Breaker HACR Breaker Usage defined by code and availability Section 6 Installation
Disconnect Located within line of sight Field-installed or factory-supplied Fused or non-fused CONDENSING UNIT FUSED DISCONNECT SWITCH Field-installed disconnect Factory-installed disconnect Section 6 Installation
Installation Consult manufacturer s instructions Locate indoor and outdoor units as close together as possible Keep refrigerant piping as short as possible Provide adequate clearance for service access and airflow Section 6 Installation
Sound Understand sound power (both indoor and outdoor) Utilize sound reduction accessories when available Consider the effect of sound when recommending unit location Isolate and support refrigerant tubing Section 6 Installation
Elevation LIQUID LINE 38AKS012-024 UNITS UNIT 38AKS 012 014 016 024 MAX ALLOW. LIFT (ft) 65 67 82 87 Max Allow. Pressure Drop (psi) LIQUID LINE Max Allow. Temp Loss ( F) 7 2 NOTE: Data above is for units at 45 F saturated suction and 95 F entering air. LIQUID LIFT Section 6 Installation
Suction Riser Refrigerant velocity in suction riser must be high enough to entrain compressor oil with the refrigerant Double suction riser or reduced diameter riser may be required Consult manufacturer s recommendations Section 6 Installation
Maximum Length of Refrigerant Piping Piping length depends on the application Heat pumps 100 linear feet Consult manufacturer s recommendations Section 6 Installation
Long Line Applications LONG LINE = 75 LINEAR FEET OR LONGER Lift vs. Run Long Lines Require: 1. Liquid line solenoid valve(s) 2. Suction line accumulator(s) LIFT Section 6 Installation
SECTION 7 SPLIT SYSTEMS Summary
Summary Identified applications that utilize the strengths of split systems Identified the components of split systems Discussed the impact that codes have on system application and selection Compared the differences in outdoor and indoor unit types Reviewed key installation issues Section 8 Summary
Work Session 1 SPLIT SYSTEMS Work Session 1 Multiple-choice questions may have more than one correct answer; identify all correct selections. 1. A typical commercial split system includes. a) an indoor unit only c) an indoor and an out unit b) a compressor, an indoor fan, an evapora- d) a compressor, an indoor fan, an evapotor and condenser as one or more rator and condenser as a package sections 2. True or False? All commercial split systems are at least dual circuit. 3. True or False? Net capacity will always be greater than gross capacity. 4. SEER applies to a. units which are cooling and heat single phase units under 65,000 Btuh Work Session 1
Technical Development Program Thank You This completes the presentation. TDP-634 Split Systems Artwork from Symbol Library used by permission of Software Toolbox www.softwaretoolbox.com/symbols