Presented by Terry Stohs Viessmann Manufacturing Company Inc

Presented by: Terry Stohs Viessmann Manufacturing Company Inc.

Design Challenges in Commercial Building. Efficiency Operational Cost Regulations System Longevity Mechanical Room Space System Integration(BMS) Customer Comfort Initial Investment Installation Cost System Design Return On Investment

What makes a Condensing Boiler Condense?

ENERGY CONTENT OF NATURAL GAS LATENT HEAT 10. 2% SENSIBLE HEAT 89. 8% Latent – Definition: Latin for “hidden” Heat that can be measured or felt by a change in temperature Nov 2005 Foil 4

HEAT RECOVERY FROM FLUE GASES Water vapor (steam) containing latent heat How do we capture the latent heat? § Simplified Chemical Combustion Formula: CH 4 + 2 O 2 CO 2 +2 H 2 O

%. 8 9 9 O E ST EM H T F NT E I FIC B ER L I O AFUE n o i t s u y b c m n Co ficie Ef Therma l efficien cy …. can reach efficiencies of 98% - and more…. . 98% EFFICIENT MARKETING AND REALITY

What Are The Test? ?

COMBUSTION EFFICIENCY TESTING For condensing gas commercial boilers >300 MBH BTS-2000 ∆T=100°F Constant Load Air Input 180 o. F Heat Exchanger Fuel Input Efficiency is manually calculated using formulas in BTS-2000 or CSA B 140. 7 - 05 Efficiency is manually calculated using formulas in BTS 2000 or CSA B 140. 7 - 05 80 o. F Condensate measured for condensing boilers test

THERMAL EFFICIENCY TESTING For commercial gas or oil boilers >300 MBH NOTE: In some appliances the combustion and thermal efficiencies are so close that thermal efficiency can actually be measured higher than combustion efficiency. This can be due to a very well insulated jacket (low standby losses), the testing environment (space QIN warmer than Return Water Heatin. Input, Temperature) and small errors the test results. btu/h ANSI Z 21. 13 / CSA 4. 9 -2007 BTS-2000 ∆T≥ 100°F TOUT Boiler TIN – Fixed water temp (35 W= Mass of 80 o. F) water (lb) Condensate measured for condensing boilers

MORE USABLE HEAT THROUGH CONDENSATION Condensing boiler Total heating value Latent heat Sensible heat Condensation Useable heat Heating system What influences the rate of condensation?

Do All Condensing Boilers Perform Equally? Remember, efficiency depends on the rate of condensate formation!

FACTORS INFLUENCING EFFECTIVENESS OF CONDENSING TECHNOLOGY Burner type Fuel Heating system Effective use of condensing technology Govt regulation Return water temp Piping layout

FACTORS INFLUENCING EFFECTIVENESS OF CONDENSING TECHNOLOGY Effective use of condensing technology Govt regulation

FACTORS INFLUENCING EFFECTIVENESS OF CONDENSING TECHNOLOGY Heating system Effective use of condensing technology Return water temp

SIMPLIFIED CONDENSING BOILER OPERATION Steady state boiler efficiency % 98 96 133 94 Dew Point of Natural Gas 92 90 88 86 84 Condensing mode Non-Condensing mode 82 80 60 80 100 120 140 160 180 200 of Boiler return water Foil 15 temp

How do we get the most from a Condensing Boiler? ? ? Make It RAIN!!! • Condensing Technology. • Rein in the energy savings. Flue gas condensing In contact with the Boiler’s heat exchanger Boiler Heat exchanger Latent energy transferred into heating system

RETURN WATER TEMPERATURE Boiler return water temperature determines condensing operation

Outdoor Reset Control Why use it? 1. Comfort § Slow space temperature changes § Constant heat output § Keep up vs Catch up 2. Efficiency § Eliminate overheating § Three to one rule § Lower standby losses

HYDRONIC WATER TEMPERATURES Boiler water temperature maintained o. F Boiler Water Temperature 195 176 Traditional boilers must be kept hot On/off control 167 158 140 o F Dew point Natural gas 133 117 104 Boiler water temperature modulated 86 72 22 +65 +50 32 +14 Outside Temperature -4 o. F

IMPACT OF SYSTEM TEMPERATURES ON CONDENSATION Supply/return temperature: 167/140 o. F §Fan §Radiators o. F 194 System water temperature 176 Condensation range 167 o. F 158 140 Dewpoint temp 140 o. F 133 o. F 122 104 86 11. 3 o. F 68 59 50 68 Outside temperature 41 32 23 14 5 o. F

SYSTEM WATER TEMPERATURE DROP 160 o. F What about a Typical system higher temperature 20 o. F Temperature drop? drop 30 o. F…… 40 o. F? 140 160 o. F

Fan Coils For Condensing Boilers 160 OF Traditional Fan Coil Sizing Air flow 150°F 140°F

Fan Coils For Condensing Boilers 170 OF Fan Coil Sizing 150°F Air flow 130°F

INFLUENCING THE RETURN WATER TEMPERATURE Let’s get creative

Hybrid System Supply System Return Condensing Boiler Non-Condensing boiler

FACTORS INFLUENCING EFFECTIVENESS OF CONDENSING TECHNOLOGY Burner type Effective use of condensing technology

Natural Gas Combustion +Excess air 1 part gas 10 parts air What happens as we increase excess oxygen to achieve better flame quality? More excess air = Lower CO 2% Lower C 02% = Lower dew point temperature Lower dew point temp. = Less condensation

Turn Down What Methods are Available? Does it Change Efficiency?

o. F 140 Natural Gas (95% CH 4) § Water vapor condenses below the dew point temperature Dew point water vapor 131 122 Higher CO 2 =Higher Dew point =More Condensation 113 104 95 Lower CO 2 =Lower Dew point =Less Condensation 86 77 2 3 4 5 6 7 8 9 10 11 12

Turn Down Methods Single unit multiple gas valves and burners High Mass boiler Multiple Gas valves single burner Low Mass High turndown Multiple boilers

FACTORS INFLUENCING EFFECTIVENESS OF CONDENSING TECHNOLOGY Effective use of condensing technology Piping layout

USE OF MIXING VALVES WITH CONDENSING BOILERS 4 -way mixing valve Boiler return water temperature elevation INCORRECT 3 -way mixing valve Lower boiler return water temperature. CORRECT

CONDENSING BOILERS IN TWO TEMPERATURE SYSTEMS High temp system Low temp system

COMBINATION OF BOILERS System Supply System Return Boiler Condensing boiler LAG BOILER Condensing boiler LEAD BOILER

Integrated solutions for all your hydronic heating and DHW needs Small Boilers Thermal Solar Large Boiler DHW

Thank You!!! Terry Stohs Viessmann Manufacturing Company Inc.