2 What will you know? What are Hybrid Systems? What is Balance Point? What is Power Consumption?What is Coefficient of Performance?What Controls?How to sell Hybrid Systems!
3 What will you be able to do? Explain and configure Hybrid SystemsDetermine Balance PointsDetermine COPsEstimate Power ConsumptionSell Hybrid Systems
4 What are you fixin’ to do? Use Perf. Data and Program to determine Balance PointUse Perf. Data and Program to determine COPsComplete Power Consumption pagesPractice the “story”GET TO WORK!!!
5 Furnace Operation HEAT Heat Loss = load in winter Gas, Propane, Oil furnace replaces heat by fuel combustionOutput/capacity constant regardless of OD Temp.HEAT
6 Heat Pump Operation Heat Loss = load in winter Heat Pump replaces heat by transferring heat from outsideOutput/capacity of HP reduces as OD Temp. dropsAir Conditioner in Reverse!
7 Air Conditioner Operation HEATEvaporator Coil absorbs heat from the ID air as liquid refrigerant evaporatesCondenser Coil releases heat into the OD air as refrigerant gas condenses into liquid
8 Heat Pump Operation HEAT Condenser Coil releases heat into the ID air as refrigerant gas condenses into liquidEvaporator Coil absorbs heat from the OD air as liquid refrigerant evaporates
9 Heat Pump CapacityAs the OD Temperature drops, the heating capacity of a heat pump drops.
10 Heat Pump Defrost Cycles Defrost Cycles are factored into heat pump performance data.
11 Manual J – Residential Load Calculation (Version-7) “The design heat loss must be calculated for the winter outdoor design temperature. Because the maximum heat loss occurs during the early morning hours, before sun rise and at a time of occupant inactivity, the heat gains due to solar radiation and internal heat gains are not considered in the heat loss calculation.”The furnace/heat pump is selected for the coldest day of the year!What about the other days???
12 Heat Loss = LinearAs the OD Temperature DROPS, the heat loss INCREASES and vice versa!
13 Balance PointThe lowest OD Temperature at which the heat pump can supply 100% of the heating required for the space.
14 Manual J: Version 7“The design heat loss must be calculated for the winter outdoor design temperature. Because the maximum heat loss occurs during the early morning hours, before sun rise and at a time of occupant inactivity, the heat gains due to solar radiation and internal heat gains are not considered in the heat loss calculation.”The Balance Point might be LOWER than you think!
15 Power Consumption $$ Heat Loss in Btus Calculate cost to replace Heat Loss in Btus - $$$Need weather dataNeed efficiency of equipmentNeed Btus of heat per unit of fuelNeed “Correction Factor"$$
17 Equipment Efficiency AFUE for Furnaces 80% or 90% Gas Furnace80% Oil FurnaceCoefficient of Performance for Heat Pumps – COP = (efficiency at a specific condition)will vary with OD Temperature!!!
18 Btu Outputs for Fuels Natural Gas = 100,000 Btu per “Therm.” (100 Cubic Feet of Gas - CCF’s)Propane = 91,500 Btu per GallonOil = 130,000 Btu per GallonElectric = Btus per Watt3,413 Btus per Kilowatt (Kw)( Kw = 1,000 watts )
19 Coefficient of Performance (efficiency at a specific condition) 1 Watt = Btus of heat1 Kilowatt = 3,413 Btus of heatHeat Pump Capacity & Heat Pump Power - KwPerformance DataCOP at the Balance Point(Heat Pump Capacity / Heat Pump Power - Kw)3,413
20 “Correction Factor”Correction Factor = adjustment applied to the number of heating load hours, given the effects of OD temperatures on structures and how these effects are delayed or diminished because of daily temperature changes – in other words, for the house to experience the full load effect of 32F (BtuH heat loss), the OD temperature must remain this low for quite a few hours. Normal daily ranges vary, which throws our calculations into disarray.Recommend beginning with 70%
21 Furnace Power Consumption Variables Heat Loss - Load CalculationHeating Load Hours - Weather DataFuel cost per unit (therm/gallon) - $Correction FactorAFUEBtus per unit of fuel (therm/gallon)Methods from Manual J: Version 7 (Appendix A-3)
22 Furnace Power Consumption Heat Loss - Load CalculationHeating Load Hours - Weather DataFuel cost per unit (therm/gallon) - $Correction FactorAFUEBtus per unit of fuel (therm/gallon)Heat Loss x Heating Load Hours x Fuel Cost-unit x Correction FactorAFUE x Btu Per Unit of Fuel
23 Heat Pump Power Consumption Heat Loss - Load CalculationHeating Load Hours - Weather DataElectric cost per Kw - $Correction FactorCOP1 Kw = 3,413 BtusHeat Loss x Heating Load Hours x Cost per Kw x Correction FactorCOP x 3,413
24 Furnace Example43,651 x x x .70.80 x 100,000$91 estimated cost of operation for this temperature range over a year period.Heat Loss at 20°F = 43,651 BtuHHeat Load Hours = 298$.80 per Therm. - Natural Gas70% Correction FactorXV80 Furnace - 80% AFUE
25 Heat Pump Example21,825 x x x .702.8 x 3,413$60 estimated cost of operation for this temperature range over a year period.Heat Loss at 50°F = 21,825 BtuHHeat Load Hours = 540$.07 per KwH70% Correction FactorXL14i - COP = 2.8