Fundamental Principle: Three-Stage Optimisation of Heat Management
What to do to make it cheap, comfortable and environmentally friendly? Should one exclude the other? The answer can only be this: heat management should always be optimised and heat regarded with respect. A statement this obvious, though as practice shows, not fully understood by some. There are three stages of the ‘heat path’: generation (i.e. heat production), heat storage (if any), and finally heat distribution. In order to see the essence of the problem, these three stages should be viewed separately.
Optimising Heat Distribution
Let us treat heat as a commodity. Since there is a product, there must be production and warehousing. From there on goes trade, then sales, and finally a customer with his diverse needs. You can optimise heat production but you may not be able to distribute it optimally. Thus, the entire benefit of optimal heat production can be frittered away by suboptimal heat distribution.
Ideally, heat should only be produced at such a time and exactly in the amount and for a duration that it is needed. We will not be able to achieve such an ideal state. However, by having appropriate knowledge about the entire heat management process, we can try to get as close to the ideal as possible.
When optimising heat production and distribution, we must take into account a number of factors, such as cost, our personal habits and needs. The type, size, technology and location of our house, as well as local conditions, including access to alternative energy sources, should also be taken into account.
Having a general idea and greater knowledge on these matters will prevent us from succumbing to commonly circulating myths and distortions. As a result, we shall not fall prey to building a house with a merely well-marketed, fashionable installation, about which we will not even be able to tell whether it has any better, cheaper to run, more comfortable and environmentally friendly alternatives. Awareness of the three-stage process of heat management, common sense and logical thinking will enable us to find optimal solutions.
Controlling the Heating Source
Some heating sources can be easily controlled and capable of generating a large amount of heat energy in a short span of time (e.g. electric boilers, gas boilers). Others can be difficult to control, though capable of generating a large amount of heat in a short time (e.g. solid fuel boilers). There is a third type – easily controllable but unable to supply a large amount of heat in a short time (e.g. heat pumps). All of them could be manual or maintenance free.
Performing even the simplest heating demand calculation will give us an idea of the required power of the heating source. It is a complete mistake to buy a larger than needed heating source ‘just in case’. The demand result should always be taken into account. In the off season, our heating needs must be at the level of the minimum power of our heat source.
Too high minimum power of the heating source will lead to the heat production being suboptimal. Gas and oil boilers, as well as heat pumps will turn on and off too frequently. Solid fuel boilers will operate at a non-optimal fuel combustion temperature preventing the full use of the calorific value of the fuel, thus leading to the heat production being suboptimal, too.
Heating Power – Things to Consider When Choosing a Boiler
In currently built warm houses there is a large disproportion between the heating power necessary for central heating and domestic hot water. Therefore it should always be considered whether using a dual-function device is more advantageous over the use of separate devices for each of the purposes (e.g. a condensing boiler for heating and an electric boiler for domestic hot water).
It is more beneficial when the power of the heat source is lower than the power of heat distributors i.e. radiators, and not the other way round. An example from another industry would say that the amplifier should not be stronger than the loudspeakers.
There is a common myth that underfloor heating prevents the boiler from frequently turning on and off. This means that the surplus heat produced by the heat source in the next cycle of its operation is deposited in the floor, regardless of whether there is a demand for it or not – a clear loss!
Neither wall-mounted nor any floor type radiators should be used to buffer excess boiler or other heat source power.
Radiators are there to optimally distribute the optimally generated heat at a time and in the amount that is needed.
If there is no heating requirement, the radiator should be able to immediately or as quickly as possible stop giving off the heat.
The Best Radiators for Heat Pumps and Condensing Boilers
Compared to the standard offer of wall-mounted radiators and underfloor heating, REGULUS-system wall-mounted and trench radiators are undoubtedly the most optimal way of distributing heat. When designing a central heating system (CHS) they allow for all three functions to be considered as a whole – optimal heat generation, optimal heat storage and optimal heat distribution according to the user’s requirements.
REGULUS radiators, due to their design which is similar to an engine coolant radiator, are characterised by high performance and high efficiency regardless of the temperature they operate at. This is down to their small mass and low water content. They work perfectly well with condensing boilers as they boast low thermal inertia and a large output surface. The percentage of necessary oversizing of REGULUS radiators for condensing boilers is smaller than it is for other radiator types.
REGULUS radiators are much more dynamic. Their low temperature performance is superior to other radiators. The thermal conductivity ratio of copper and aluminium is higher than that of steel or aluminium itself. Therefore, REGULUS radiators are much more efficient in carrying heat from the heat source.
Radiators with a Fan for an Increased Dynamics of Heating
REGULUS-system also offers radiators equipped with a quiet-running fan (E-VENT series). They are able to output a heating power over 30% higher than standard radiators without the need for size increase. E-VENT radiators allow you to quickly heat rooms which are less frequently used or are only used for a short part of a day.
REGULUS REVERS radiators are an excellent choice for all types of heat pumps, as they support effective central heating and cooling in the summer.
REGULUS radiators are one of the very few radiators which can work without the risk of corrosion in an open system solid fuel boilers. What is more, they do not affect their warranty. These boilers should operate at their optimal power, as they may produce heat in excess, especially when using fuel with variable calorific value and in periods of variable insolation. Owners of solid fuel boilers should always have a buffer tank built into the installation that is appropriate for the size of the house and the power of the boiler.
Thermostatic valves should not be used in installations without a heat buffer tank, because closing them may cut off a large part or even the entire installation from heating circulation. In these types of installations it is best to close the radiators with ordinary ball valves, as they have the highest flow rate. The central heating installation should always be designed as if it was for gravity circulation with a slope and without siphons, so that in the event of a power failure it will continue operating.
The Principle of One Buffer
Designing an installation in the form of: heat source – buffer – underfloor heating, is an example of non-optimal heat distribution. There is nothing optimal in creating two large heat buffers. After all, underfloor heating in itself is a gigantic heat buffer with the only difference being, that in a classic buffer heat is kept ‘for later’, while the heat introduced to the floor is emitted instantly.
Does a manufacturer (say heat source) manufacturing a product (say heat) put all the manufactured goods out on the market at the same time, regardless of whether they are in demand or not? The ‘single buffer rule’ applies.
In an ideal scenario we should be able to produce and distribute heat without the need to store it. If we have to have a heat buffer it should be well protected against heat losses. To put it simply – heat on demand when and as needed!
The so-called ‘self-regulation of underfloor heating’ is not a feature of underfloor heating system, but a feature of a concrete floor with its enormous heat capacity. The weight of 1m2 concrete floor ranges from 150-350 kg.
REGULUS radiators are highly resistant to corrosion – hence they are ideal for swimming pools, car washes, winter gardens and many more. They perform well in installations powered by pressurised steam, i.e. industrial plants, bakeries, laundrettes, etc.