We analyze how domestic hot water (DHW) equipment influences the energy rating.
In this article we intend to carry out an analysis of how the type of domestic hot water equipment influences the energy rating with the CE3X program, first of all we will consider that the equipment used most frequently are the ones gas instantaneous heaters, electric accumulators or oil or gas boilers, being evident that those that work with electricity are going to penalize them to a greater extent than those that work with other types of energy such as natural gas, butane, propane, etc….
Likewise, in those equipments that accumulate hot water to be used, even though they are well insulated, they lose heat and therefore are less efficient, as is the case with electric storage heaters.
We are going to carry out an example in the energy certificate of a home so that we will make three assumptions, in the first case we consider an instantaneous natural gas heater, in the second case we will replace it with an instantaneous electric water heater and in the third case we consider a thermos. electric with accumulation.
Characteristics of the property:
It is an individual block house located on the second floor, whose construction year is 1978, with a useful habitable surface of 34.56 m2, located in Valencia capital, said house has a main north-facing façade and two patio facades interior lights with east and south orientation.
This house has a thermal envelope formed by three facades, one facing north, and two facing east and south, all three falling onto the interior patio. The partition with a common area is also considered, as well as the dividing walls of the house or separating walls from other houses.
Fixed air conditioning installations of the property to be certified:
In this case, the house, together with the DHW installation, has a very efficient air conditioning system with three split-type wall units with an inverter heat pump, covering the demand of the living-dining room as well as the two bedrooms of the house. These equipments are left in the three assumptions that we are going to consider, in addition they are less than 5 years old with what they present a very high seasonal performance in heating and cooling.
First assumption: Natural gas heater in the energy rating.
In this first case, it is considered that the home has an instantaneous natural gas heater, with a nominal power of 26.8 Kw and a combustion efficiency of 85%, and we obtain an E rating.
Second assumption: Instantaneous electric heater in the energy rating.
In this second case, it is considered that the home has an instantaneous electric heater, with the seasonal performance estimated from the age of the equipment (between 5 and 10 years), and, despite the fact that we have worsened the rating, we continue to obtain a rating E.
Third assumption: Electric heater with storage and its energy rating.
In this third case, it is considered that the home has an electric storage heater with an accumulation volume of 80 liters, so that the performance with the seasonal performance is estimated from the age of the equipment (between 5 and 10 years), and it has penalized us to the point of lowering two letters, obtaining a G rating. What seems to be clear in the latter case is that ACS equipment that works with electricity and has accumulation significantly penalizes the energy rating.
We already know a little more about the efficiency of the equipment and its calculations, now it is time to know how to program the heating in winter with tips to have a lower energy consumption.
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Article prepared by José Luis Morote Salmeron (Technical Architect - Energy Manager - Google plus profile) Access to his website HERE, in collaboration with OVACEN.
