ChartHeat Pump Energy Efficiency Evaluator for Ground Source Heat PumpsQuestionsanswersvaluesFactorResultnotes(Very simple version)Modified1/27/08Notes: This calculator is for educational purposes. It is not a design tool.1Type of heat pumpGround source2The figures can only be used a s a rough guide since many factors effect the actual efficiencySpring source, directfactor cells e6:e10MinMaxmin dottedSpring source, indirectNOTE, factors small since alloThe energy efficiency of any heat pump system2.5402.5radslarge radUH woodUH screedradslarge radUH woodUH screedis dependant on many things.2.5402.5ground factor2Type of houseOld building, solid-walls badly insulated house.3145383025165585045Select options below, and see how2.5402.5collector sizeCavity walls, double glazing to old specification.238312419258514439temperatures change. The efficiency2.5402.5evap sizeWell insulated building to 2002 regulations332262015352464035is displayed here.04040Condenser sizeWell insulated building to 2007 regulations428231712448433732Energy EfficiencyCOP3.8Super insulated Eco-home523181410543383430(Coefficient of Performance (COP), is the ratio of heat output to energy input)surface/water in.3Type of emitter (radiators etc)Radiators312032Enter your heat pump size here7.0kWRadiators of very large area (or cheap underfloor)226Electric input (when running)1.9kWUnderfloor heating, wooden. (or poor screed type).320Underfloor screed with solid / tiled covering.415Temperature Difference37.5C(Distance between 'hot' and 'cold' parts of heat pump)4Underfloor heating designStandard (as used with boilers)2531/2 of expected temp diff.Ground temperature10CLow temperature design. (for heat pump)3Glycol (brine) temperature2.5Cevap dt.condHeated water temperature (flow)40C5Heat pump unit efficiencyHigh quality, optimised for heating155(Most well-known heat pump types)3.53.5this is difference for both evap and cond.Room temperature20CLower quality (cheaper)85.6factor for evap. But x 0.7 for condenser.multipliedgroundglycolwetnormdrywetnormdryType of houseGround collector area6Ground collector areastandard area111773.753.75Standard soilstd sizelarge22.753.587.256.5Note; This chart demonstrates only the most important factors that affect the energy efficiency of a heat pump system. See the more complex version for more details Each heat pump installation should be considered in its own right. The chart was designed as an teaching aid rather than a design tool.Large area3212.752.75Large areamed33.754.7576.255.25Small area5ground3555Small areasmall456654Type of emitter (see note below)Ground conditions3.75933wetstd size911.514.2534.757Ground conditionsStandard ground177glycol2722wetLarge areaWet ground93.754544wetSmall areawetnormdrywetnormdryRequired room temperatureGeographical LocationDry ground11114.754.75drystd sizelarge22.753.564.53333.53.5dryLarge areamed33.754.7542.50.51Old building, solid-walls badly insulated house.18.25566drySmall areasmall45620-2* Note; These estimations are based on average winter figures, not worse-case figures.www.heatpumps.co.uk2Cavity walls, double glazing to old specification.16.334.7534.75911.514.2534.75* Underfloor designs vary greatly, resulting in different working temperatures.Copyright: John Cantor 20073Well insulated building to 2002 regulations2.83temperature drop in indirect heat-exchanger* During long cold periods, the source temperatures will drop below figures given above.The coefficeient or Performance (COP) is a measure of the energy efficiency of a heat pump. The higher the number the betterExample:- a 10kw heat pump with a COP of 4, would use 2.5kW of electricity when it is running.The white cell ;- "Enter your heat pump size here", simply calculates the electrical power input.8Required room temperatureAverage12020simply modifies room temp.Quite warm22A few notes for the confused;Background heat only18The chart shows the temperature of the ground on the left, and the tempeature of the inside of your house on the right.multiplier to modify COPThe red line represents the work that the heat pump has to do to be able to extract heat from your garden, and reject it to your home.9Back-up electric heating?No electric back-up311Use 'no electric back-up' if wood fired back-upAs can be seen by changing various things, the temeprature difference (distance between the two dotted lines) changes too.Electric back-up (smaller heat pump)0.8The closer the lines are together, the better the energy efficiency.Electric back-up (If max. temperature exceeded)1difference, if >0 then temp has exceeded, COP = 1exceeded byexceeded by%age of total lift%age of 10%age with max of 100%if heat pump max temperature is exceeded.62-22-220001ground10Geographical LocationDefault (UK)10010North East, Scotland-110South West.1simply modifies ambient temperatureHeat pump run hoursNormal hours running per year (default)111Light use of heat pump. Woodstove backup etc.0.8High run hours: swimming pool, or small-sized heat pump.1.400500060007000

Chart

DataMinMaxdottedtop dottedThe distance between two dotted lines represents the temperature 'lift' that the heat pump works against. The closer together, the higher the energy efficiencyTemperature, Degrees CelsiusHeat Pump Temperature 'Lift'.

John Cantor:min refrig tempJohn Cantor:max refrig tempJohn Cantor:lower plot line,( red dotted)John Cantor:returned figureJohn Cantor:deviation from UK average ground tempJohn Cantor:result from drop-down selectionJohn Cantor:factor I have written inJohn Cantor:this is returned from drop-down. I.e. 1,2,3 etc.John Cantor:John Cantor:made-up numbersJohn Cantor:temp diffground to ground in trenchJohn Cantor:temp diffground to glycolJohn Cantor:this is result