Gas Heating with Absorption Heat Pumps – How, Where and Why June 04, 2019

Stone Mountain Technologies, Inc.

Michael Garrabrant, President Johnson City, Tennessee, USA www.StoneMountainTechnologies.com

Confidential 1 The World Gas Engineers Now Live In

“The world is going to end in 12 years” “We need to stop using all carbon fuels, immediately” “The world is going to end in 10 years” “We will ban all gas by 2050” Global Warming! The world has already ended.... Climate Change! MeIting Icecaps! Rising Oceans!

Confidential 2 3 Agenda

➢ Types of gas heat pumps ➢ How does an absorption heat pump work? ➢ History of absorption heat pumps ➢ Best applications of absorption heat pumps ➢ Why do absorption heat pumps matter?

Confidential 4 Types of Gas Heat Pumps

➢ Gas-Engine Heat Pumps

➢ Heat Engines (Stirling/Vuilleumier)

➢ Adsorption

➢ Absorption

Confidential 5 Gas Engine Heat Pumps

Photo Courtesy Illios Photo Courtesy Intellichoice

Confidential 6 Gas Engine Heat Pumps

• COP Water Heating at 75F Ambient ~2.0 • COP Space Heating at 47F Ambient ~1.3 • Commercial Sizes Only (100 to 500 kbtu/h) • Hydronic or Direct Refrigerant Delivery

• Very High Capital Cost • Engine Maintenance/Cost • COP Decreases Sharply as Ambient Decreases (vapor compression cycle) • Areas with High Electric Rates/Demand Charges • Most Popular in Japan

Confidential 7 Heat Engines

Confidential 8 Direct Compression Vapor Compression Cycle

Figures Courtesy BoostHeat Confidential 9 Heat Engines

• COP Space Heating at 47F Ambient ~1.4 to 2.0 • Hydronic Delivery • Hot end 1000+ oF and psig

• Helium or CO2 working fluid (gas)

• Very High Capital Cost • System available in Europe at $250/kbtu/h • typical condensing furnace ~$25/kbtu/h • Direct-compression system requires boiler for low ambients

Confidential 10 Adsorption Heat Pumps

Solar-Thermal Adsorption Chiller Photo Courtesy Climatewell Absorbent is a Solid

Confidential 11 Adsorption Heat Pumps

• Water – Salt or Water – SilicaGel (cannot be used for heating) • Ammonia – Carbon or Ammonia – Salt • Other exotic combinations...... • Hydronic Delivery • COP Space Heating at 47F Ambient ~ 1.2

• Large Size, Heavy, High Capital Cost • Low heat/mass transfer coefficients, poor internal heat recovery • Normally used for cooling using low-temperature waste/solar energy

Confidential 12 Absorption Heat Pumps

Figure Courtesy Robur Absorbent is a Liquid

Confidential 13 How do Absorption Heat Pumps Work?

Confidential 14 How Does It Work?

Vapor Compression Heat Pump Gas-fired Absorption Heat Pump

COPh = Qcond/Ein = 3.0-4.0 COPh = (Qcond + Qabs)/Qin = 1.4-2.0 Qheat = ~1.1 x Qcooling Qheat = (Qcond + Qabs) ~ 2.5 times Qevap Capacity & COP Remain High at Low Ambient Temperatures Confidential 15 What happens when it gets cold outside?

Confidential 16 Pause For A Few Definitions

COP (Coefficient of Performance): Useful Energy Produced ÷ Energy Input • Cycle • Gas-Fired or HHV (includes combustion loses) • Electrical Parasitic Included?

Beware • HHV or LHV • Ambient Temperature • wet or dry ambient sink • Chilled/Hot Water Delivery Temperature • With or Without Electrical Parasitic Power • Energy Source: Site or Primary Basis

17 Two Commonly Used Absorption Cycles

NH -H O Absorption 3 2 LiBr-H2O Absorption*

❖ Cooling COP(SE) = 0.65 Cycle / 0.5 Gas ❖ Cooling COP(SE) = 0.7 / 0.55 ❖ Cooling COP(GAX) = 0.83 Cycle / 0.7 Gas ❖ Cooling COP(DE) = 1.2 / 1.0 ❖ Refrigeration COP(SE) = 0.5 Cycle / 0.4 Gas ❖ Cooling COP(TE) = 1.55 / 1.3 ❖ Heating COP(SE) =1.7 Cycle / 1.5 Gas ❖ Heating COP(GAX)* = 2.1 Cycle / 1.8 Gas ❖ Large Gas-Fired Cooling (100+ RT) ❖ Large Waste/Solar Cooling ❖ Gas-Fired Heating ❖ Commercial/Industrial ❖ Small Waste/Solar Cooling ❖ Residential/Light Commercial * All applications require wet cooling tower * GAX advantage = minimal below 30 oF

Confidential 18 Two Commonly Used Absorption Cycles

LiBr-H O Absorption NH3-H2O Absorption 2

❖ Reversible (heat or cool) ❖ Non-Reversible (cooling only) ❖ Direct Air-Cooled ❖ Requires Wet Cooling Tower ❖ Can do Refrigeration ❖ Cannot do Refrigeration ❖ Small Footprint ❖ Large Footprint ❖ Lower Cost/RT in Smaller Systems ❖ Higher Cost/RT in Smaller Systems o o o ❖ SE (220oF) or GAX (400oF) ❖ SE (180 F), DE (350 F) or TE(>500 F)

Figure Courtesy Robur Figure Courtesy York Confidential 19 For Remainder of Presentation

Focus on Heating Using NH3-H2O Cycle

Confidential 20 NH3-H2O Cycles

GAX

Double Effect

Single Effect (SE)

Confidential 21 Single Effect Heating Cycle w/Condensing Heat Exchanger

Hydronically-Coupled to Building or Storage Water Tank

Confidential 22 High Pressure Side

Rectifier Vapor To Condenser , 99.9%, ~155 oF Strong Solution from Solution Pump ~ 220 oF 50% NH3, ~ 110 oF 97% NH3

To Absorber o Desorber ~135 oF ~ 120 F ~ 215 oF

Solution Heat Exchanger (SHX) Hydronic Fluid Being Heated ~ 100 oF

To Sub-Cooler ~117 oF Weak Solution 15% NH3, ~270 oF High Side Pressure 200 – 370 psig Depending on Hydronic Return Temperature Confidential 23 Low Pressure Side

o ~ 120 F NH3 Vapor ~43 oF Weak Solution Air o 15% NH3, ~135 oF ~ 105 oF ~ 48 F EEV NH3 LP Liquid Evaporator ~37 oF

Refrigerant Heat Exchanger (Sub-Cooler) Absorber (RHX)

NH3 HP Liquid from Condenser ~115 oF

Strong Solution To Rectifier Coil Hydronic Fluid ~ 110 oF, 50% NH3 Being Heated Low Side Pressure o Solution Pump ~ 100 F 0 - 120 psig Dependent on Ambient Temperature

Confidential 24 Solution Pump

Very Difficult Pump Application • Solution at or near saturation (can flash in pump) • Often required to pump 2-phase vapor/liquid • Inlet pressure can be at a slight vacuum • Outlet pressure up to 390 psig

• Viscosity very low, less than water • Very poor liquid lubricity • Cannot leak

• Oil-driven diaphragm or piston pumps normally used

25 Evaporator Boiling Temperature Profile

• 2-Component Mixture

• EEV Controls a Glide, Not Superheat

• Proper Glide Very Critical for Maximizing Performance at all Operating Conditions

Confidential 26 Single-Effect Cycle Performance vs Operating Condition

Confidential 27 Brief History of NH3-H2O Absorption

Confidential 28 First Absorption Refrigerator - 1859

Ferdinand Carré

• H20 / NH3 refrigerant pair • Heat – driven • Produced “artificial ice” in large commercial quantities • Patented France (1859) US (1860)

Confidential 29 First Residential Gas-Fired Air-Conditioners

Bryant, 1962-1970 (COP 0.28 – 0.42) Arkla-Servel, 1965 (COP – 0.33)

Confidential 30 Whirlpool, 1965 – 197x (COP - 0.50)

Confidential 31 Arkla-Servel, 1968 (COP – 0.48)

Confidential 32 Columbia Gas of Ohio, 1972 (COP - 0.40)

Never Commercialized

Confidential 33 Robur, 1991 to Present

2004 – GAX Heat Pump 0.60/1.26 COP

Confidential 34 Energy Concepts

Confidential 35 1980 – Almost 40 Years Ago......

DOE and Gas Utilities Launch Series of R&D Programs to Develop Gas-Fired Residential Heat Pump

“Search for the Holy Grail”

Gas-Fired COP Goal: 0.7+/1.2+ Cooling Focus – Heating an Afterthought

Gas Utilities Want To Sell More Gas In Summer Peak Load Reduction Typical EHP SEER ~5-7

Confidential 36 Columbia Gas of Ohio, 1988 (COP - 0.80/1.55)

NH3-H2O Double Effect • High Side Pressure >1500 psig !!! • Abandoned, not cost effective

Confidential 37 Battelle/GRI Dual-Cycle (1983 – 1990)

SE NH3-H2O Cycle + SE LiBr-H2O Cycle Operating in Series

Never Commercialized, Too Expensive/Complicated

Confidential 38 Phillips Engineering, 1981 to 2000

❖3 RT GAX Heat Pump ❖Target 0.8/1.8 COP ❖Proprietary Cycle ❖Proprietary HXs ❖Magnetic Piston Pump ❖DOE Supported

Never Commercialized, Too Expensive/Complicated

Confidential 39 Cooling Technologies Inc., 1997 to 2003

❖5 RT GAX Chiller, Target 0.7 COP ❖Proprietary HXs ❖GRI Supported

Field Tested, UL Approval, Not Commercialized: Not competitive vs electric air-conditioners Confidential 40 Ambian, 1999 to 2004 (COP – 0.70/1.40)

❖ 5RT GAX Heat Pump ❖ Attempt to Salvage Phillips Intellectual Property ❖ DOE/Gas Utility Supported

Never Commercialized, Too Expensive/Complicated SMTI GAHP (2010 – Present)

10 kBth 20 kBth 80 kBth 140 kBth

Single Effect NH3-H2O Cycle Focus on Heating only, Reducing First Cost

Confidential 42 Best Applications for Gas-Fired Absorption Heat Pumps

Confidential 43 GAHP Applications

Space-Water-Pool Heating • COP ~ 1.4+ compared to <1.0 for condensing • Cool-Cold Climate Space Heating • All-climate Water Heating • All-climate Pool Heating

Cooling not a Great Option, except • “Free Cooling” while Water Heating • Using Waste Heat as Energy source

Confidential 44 Residential Forced-Air Space Heating

Confidential 45 Residential Hydronic Space Heating

Confidential 46 Residential Water Heating

❖ Fuel Sources: Natural Gas, Propane ❖ COP: 1.40 average recovery at 68oF ❖ Expected UEF: 1.20 ❖ First Hour (tank) Capacity: 60-80 gallons ❖ Heating Output: ~10,000 Btu/hr (3 kW) ❖ NOx Emissions: < 10 ng/J ❖ Refrigerant GWP: None

❖ Location: Conditioned or semi-conditioned space ok ❖ Venting (condensing operation): 3/4 - 1” PVC pipe ❖ Condensate management: As per local code ❖ Electrical requirement: 115 VAC / ~1 amp ❖ Supplemental heating capacity: Available for high loads (1.2 kW element)

Confidential 47 Commercial Water Heating

Food Service, Hospitality, Laundry, etc…)

Strategies: ➢ Baseload / Peak load ➢ Extend life of existing tanks With Cooling, COP =2.0

Multi-Family, Medical, Office, etc

Strategies: ➢ Baseload / Peak load ➢ Extend life of existing boilers Why do Gas Absorption Heat Pumps Matter?matter?

Confidential 50 Space & Water Heating Require a lot of Energy

Confidential 51 CO2e Emissions

eGrid 2016 US Avg Calif.

Nat. Gas Baseload vs Non-Baseload Grid Emissions is CRITICAL (lbs / therm) 11.69 11.69

Elec. - All output (lbs / kWh) 0.99 0.53 Use Non-Baseload When • Fuel-Switching • Adding/Subtracting Load from Grid Elec. - Non-Baseload (lbs / kWh) 1.50 0.94

Confidential 52 Seasonality & Time of Day Matter.....A Lot

California Grid Emissions vs Natural Gas

Courtesy California Energy Commission Confidential 53 Residential Water Heating CO2 Emissions

Confidential 54 Residential Water Heating Economics

Utility Costs US Calif. Lifecycle Cost (12 yr) US Average Avg by Technology & Region California Nat. Gas ($ / $1.25 $1.19 $6,000 therm) Electricity ($ / $0.12 $0.19 $5,500 kWh)

$5,000

$4,500

$4,000 GHPWH EHPWH Std Gas Non-Cond Cond Tankless Storage Tank Tankless

Confidential 55 Space Heating

CC-EHP = Cold-Climate Electric Heat Pump. EHP = Standard 8 HSPF Electric Heat Pump

Confidential 56 Space Heating Example: Operating Costs

Method and Assumptions

• 2,700 sqft home • 4 occupants • Space-heating load only • EIA 2018 energy prices by state • Energy Planning Analysis Tool (GTI – based on EnergyPlus) • Performance: mfr data except GAHP (prototype test data)

http://epat.gastechnology.org/

Confidential 57 Compared to Cold-Climate Electric Heat Pump

Confidential 58 Space Heating Example: CO2 Emissions

Confidential 59 Compared to Cold-Climate Electric Heat Pump

Confidential 60 Space Heating Example: NOx Emissions

NOx Emissions by Technology and Geography Furnace 80% 35 Furnace 96% EHP HSPF 9.0 30 GAHP 140% 25

20 Space Heating Example: CO2 Emissions

15 Annual Annual Lbs 10

Confidential 61 GAHPs Leverage Future Renewable Gas

% Renewable in Delivered Heat

GAHP vs. Condensing Furnace/Boiler

Confidential 62 A more economically viable path to decarbonization?

Is this a discussion about electricity vs. thermal fuels?

Or is it one about the fastest and lowest cost method to decarbonize heating?

Confidential 63 Thank You !

Michael Garrabrant [email protected]

Confidential 64