high efficiency heat pump for heating, electrical characteristics and estimates of consumption
Question, *** Contributed by gsa @ libero.it, 26 06 2010
Hello, I'm a customer who in April I bought the solar panel, solar disk for the new house. This time I would bother to ask for advice. I am writing because I recently purchased 2 conditioning heat pump class AA double Daikin FTYN35GX and FTYN50GX like those I saw on the vs site, but I could not use them to do well for heating. When the outside temperature goes below 10 degrees feels a significant decrease in performance and are forced to turn on the boiler. In the new house are in the process of preparing the new heating system. I heard a lot of good high efficiency heat pumps for heating do winter, but I did not understand what they are and what characteristics must possess? I would not make the mistake of buying products not suited to heating degree I would be if I set out what are the features to find the best cars and how do I calculate the cost of the heat pump compared with the boiler plant. Regards Sav Thurs *** ***
response, sent by ecotecna@gmail.com, 29 06 2010
Ecotecno - Dear Sav Thurs *** *** regards Daikin air conditioners that you mentioned, such models on / off in this case, to make warming winter you had to use two size instead of 18000 BTU and 12000 BTU 24000 BTU 18000 BTU's instead. In other words you have purchased air conditioners to make the heat required in winter it is always recommended to be oversized, but at this point it is clear that the power consumption becomes so high that the spending bill can match that of the gas and you lose the convenience.
We come to reply on high efficiency heat pumps for a real winter heating. We will try to give an answer that might be useful to all those who want to do with this heating technology to reduce energy costs.
First, it is important to point out that everyone in the room air conditioners are Class AA, but very few people with the characteristics of high efficiency for heating, so the energy class AA does not say anything about the convenience for the winter heating .
features on which to focus attention are: a high COP at partial loads , a large air flow and minimal absorption is very low.
features on which to focus attention are: a high COP at partial loads , a large air flow and minimal absorption is very low.
For example, a 9000 BTU air conditioner for winter heating should have:
- A COP (WC / Wa) at least a partial load of 7.50, leaving in the tables that matches the value in standard conditions and may be fictitious.
- The minimum flow rate must be greater than 6.5 cm / min. heating mode.
- absorption minimum must be less than 150 W (0.150 kW) in heating mode.
These three features are essential for create a real energy savings that will result in an economic benefit.
Calculations of energy efficiency (this paragraph has a more technical content, for those who lack knowledge of math you should skip to the section of the estimate of expenditure ....)
Let consider a high efficiency heat pump with 10000 BTU of power at partial load can deliver about 3300 W / h of heat absorption of about 0.44 kWh of electricity. Considering that on average in a domestic environment requires at least 45 W / m for a comfortable interior temperature of 20 ° C, then the unit will be heated a room of 3300/45 = 73.33 cubic meters in the case of a local height of 2.7 m corresponding to a surface of about the same 73.33 / 2.7 = 27.16 square meters. So, to heat a square meter dwelling you should consume about 0.44 / 27 = 0.0162 kWh of electricity per square meter .
With a system with radiators to heat a room of 50 square meters with a height of 2.70 m takes about 0.30 m³ / h natural gas is approximately 0.30 / 50 = 0 , 0060 mc / h of gas per square meter of usable area .
At this point should be taken into account Prices in the bill for electricity and natural gas, the best way is to add the kWh and cubic meters for the last 6 or 7 bills and divide by the total expenditure. This will easily get the average price per kWh of electricity and cubic meter of gas, including all taxes, incidental expenses, the rent etc..
From the data of our customers in Campania we got a average price of € 0.166 / kwh electric than average price of € 1.01 per cubic meter of gas .
Therefore with high efficiency heat pumps alimentate elettricamente a parità di condizione si può riscaldare un metro quadro di abitazione con una spesa di 0,166x0,0162= 0,0026 €/mq .
Con un impianto a termosifoni si può riscaldare un metro quadro di abitazione con una spesa di 1,01x0,0060= 0,0060 €/mq .
Stima della spesa in bolletta
Per cui nell'ipotesi di dover riscaldare quattro locali per un totale di 90 mq per 150 giorni all'anno per sole 4 ore al giorno nel caso dell'impianto di riscaldamento a gas la spesa prevista sarebbe di circa € 324.00 , using heat pumps would be spending € 140.40 .
If we are in presence of 6 rooms for a total of 150 sq m heated to 180 days per year for 8 hours a day, with the expense of gas boiler would € 1296.00 for the spending the same conditions with high efficiency air conditioners would € 516.00 .
course, these machines should be carefully chosen and well-dimensioned considering in what locations is convenient to install than installing a traditional heating system. So I would see that we should send a plan indicating which local housing aims to provide a heat pump and as a radiator. Can send faxes to the plan 0823/1780109, thanks.
Calculations of energy efficiency (this paragraph has a more technical content, for those who lack knowledge of math you should skip to the section of the estimate of expenditure ....)
Let consider a high efficiency heat pump with 10000 BTU of power at partial load can deliver about 3300 W / h of heat absorption of about 0.44 kWh of electricity. Considering that on average in a domestic environment requires at least 45 W / m for a comfortable interior temperature of 20 ° C, then the unit will be heated a room of 3300/45 = 73.33 cubic meters in the case of a local height of 2.7 m corresponding to a surface of about the same 73.33 / 2.7 = 27.16 square meters. So, to heat a square meter dwelling you should consume about 0.44 / 27 = 0.0162 kWh of electricity per square meter .
With a system with radiators to heat a room of 50 square meters with a height of 2.70 m takes about 0.30 m³ / h natural gas is approximately 0.30 / 50 = 0 , 0060 mc / h of gas per square meter of usable area .
At this point should be taken into account Prices in the bill for electricity and natural gas, the best way is to add the kWh and cubic meters for the last 6 or 7 bills and divide by the total expenditure. This will easily get the average price per kWh of electricity and cubic meter of gas, including all taxes, incidental expenses, the rent etc..
From the data of our customers in Campania we got a average price of € 0.166 / kwh electric than average price of € 1.01 per cubic meter of gas .
Therefore with high efficiency heat pumps alimentate elettricamente a parità di condizione si può riscaldare un metro quadro di abitazione con una spesa di 0,166x0,0162= 0,0026 €/mq .
Con un impianto a termosifoni si può riscaldare un metro quadro di abitazione con una spesa di 1,01x0,0060= 0,0060 €/mq .
Stima della spesa in bolletta
Per cui nell'ipotesi di dover riscaldare quattro locali per un totale di 90 mq per 150 giorni all'anno per sole 4 ore al giorno nel caso dell'impianto di riscaldamento a gas la spesa prevista sarebbe di circa € 324.00 , using heat pumps would be spending € 140.40 .
If we are in presence of 6 rooms for a total of 150 sq m heated to 180 days per year for 8 hours a day, with the expense of gas boiler would € 1296.00 for the spending the same conditions with high efficiency air conditioners would € 516.00 .
course, these machines should be carefully chosen and well-dimensioned considering in what locations is convenient to install than installing a traditional heating system. So I would see that we should send a plan indicating which local housing aims to provide a heat pump and as a radiator. Can send faxes to the plan 0823/1780109, thanks.
