Heat pumps and gas boilers have made a lot of headlines in the last two months. It has even been said that the European Union (EU) would prohibit the use of boilers and it is totally a lie. Once the noise has passed, we will try to address the issue without demonizing any type of technology and orienting it more towards a practical exercise in order to determine which is the best option based on each case.
The debate on residential decarbonization in Spain has opened a new struggle between electricity and gas companies, since this sector is responsible for around 12% and 15% of total emissions. The former consider that the heat pump is a solution capable of providing heating, cooling and domestic hot water with a single piece of equipment and that, therefore, is useful throughout the year. For their part, the latter defend that other solutions such as high-efficiency boilers that consume renewable gases such as biomethane, a renewable gas produced from organic matter, should also be taken into account.
Well, there are several types of heat pumps and air-air ones are the most common in Spain. They obtain heat from the thermal energy of the ambient air and transfer it to the air of the location to be heated. On the other hand, in air-water systems, heat is obtained from the air and transferred to the heat transfer circuit for the distribution facilities. Finally, in water-water systems, heat is acquired from a water circuit in contact with a heat source and transferred to another, which is the heat transfer circuit of the distribution facilities.
Heat pumps spend 70% less
Among the main advantages of the heat pump are energy savings, since it supplies more useful energy than it uses for its operation and spends 70% less compared to other conventional systems under high efficiency conditions. It must be taken into account that the performance of this equipment can reach values well above 100% in ideal weather conditions and with continuous operation.
Another of its attractions is low maintenance and that the user can access public aid for its installation. On the contrary, the acquisition cost is high if you want to have highly efficient operation and consider renewable technology. According to a study by the Naturgy Foundation, the complete replacement of an old installation with a heat pump that meets renewable criteria can reach 50% of the average annual income of a Spanish home – between 10,000 and 20,000 euros -, in addition to requires increasing the power to be contracted between 1.5 and 4.5 additional kW.
Likewise, in bibloc pumps – equipment made up of two separate units on the outside and inside – space can be a problem. The indoor unit may look like a refrigerator. It is also important to note that it is difficult to extract heat from excessively cold air, so its most optimal use is in temperate places. In fact, a report from the Naturgy Foundation shows that Spain has climatic zones in which heat pumps are economically inefficient solutions and may not obtain renewable status.
The document also warns that although installations based on heat pumps can be an efficient option from the energy point of view (considering only the equipment), their application as a low-emission technology is influenced by the electricity supply, the availability of renewable energy sources and the reinforcement of distribution networks.
300,000 heat pumps installed per year
The rate of installation of heat pumps has increased in recent years, reaching an average of approximately 300,000 per year, although if the hours of operation and the associated energy consumption are analyzed, it is found that in the case of the aerothermal . ia The equipment would not be used for heating purposes, nor would it be used efficiently. According to the report, 25% of the heat pumps installed are intended for heating uses, while 75% are used for cooling. A study by the Sedigas employers’ association indicates that changing all current boilers for heat pumps would have a cost of about 201.3 billion euros, which would be 15 times the price of changing old boilers for high-efficiency models – which would require a investment of 13,421 million euros.
In this sense, in areas with socioeconomic barriers, the promotion of higher efficiency renewable heat equipment (not only heat pumps) and the replacement of conventional boilers with high efficiency condensing boilers may be another option. The boiler is the most used system to date and is based on the use of a fuel to heat water and subsequently transmit the heat through a water circuit.
Boilers have evolved their use and typology and have now been adapted to different regulations. Currently, for the purposes of installing new equipment, only high-efficiency condensing boilers are considered to the detriment of conventional boilers, which produce higher emissions and do not have heat recovery. The new equipment is capable of recovering residual heat from the exhaust gases and in the form of water vapor to return it to the system. In this way, it consumes less fuel and produces fewer emissions.
Biomethane potential
This is where renewable gases come into play, since there are boilers that do not require modifications in case of consumption of renewable gases such as biomethane. In this sense, for a heating system to be recognized as renewable does not depend on the technology it has, but on the fuel it uses, which is why gases of renewable origin are presented as another option to achieve residential decarbonization. There are also electric and biomass ones. However, biomethane has yet to be developed on a large scale and Spain has the potential to play a significant role, with up to 163 terawatt hours (TWh) per year.
Naturgy alliance and aedas homes
The two companies will bring renewable gas to housing development. They will install systems that enable the supply of biomethane in around 500 houses that the real estate developer has under development.
High efficiency boilers achieve a reduction in energy consumption of 30% and, therefore, significant economic savings on the fuel bill. Reduce nitrogen oxide and carbon dioxide emissions by up to 70% when working at low temperatures. For its part, among the drawbacks, the need to install a drain to eliminate condensate and a smoke evacuation outlet stands out.
