Energy efficiency is the greatest objective of nearly every environmental and cost conscious household today. Achieving that objective requires the installation of appliances and complimentary devices, which conserve heat, prevent heat loss and extract the maximum amount of output from the minimum amount of input.
From the perspective of looking at achieving greater boiler efficiency, it is interesting to examine how introducing complimentary devices improves the overall operation of the boiler and system.
Modern condensing gas boilers are extremely efficient at producing hot water for heating and domestic use. They supply on demand as and when it is required. With a combi boiler, when a demand for domestic hot water creates a pressure differential in the domestic hot water supply, the boiler senses the differential and springs to life producing almost instantaneous hot water.
The boiler responds to a command.
Like a pressure differential, a thermostat provides a command. The command is either to operate the boiler or to turn the boiler off. It can also command valves to open and close.
Some boilers even incorporate a thermostatic control to command the boiler to operate when ambient temperatures fall below a certain level and act to prevent the boiler and its internal pipes from freezing.
A basic room thermostat will monitor the temperature of its surroundings. It can be set to operate at a certain temperature. If the temperature falls below the desired temperature, it will command the boiler to start. As the temperature rises and exceeds the desired level, the thermostat will instruct the boiler to stop.
This simplistic thermostatic operation forms the basis of controlling the environment that the boiler’s central heating facility is designed to satisfy.
It is also the regulating device that maintains an adequate supply of stored hot water in a domestic hot water cistern.
On very basic central heating systems, one wall mounted thermostatic control is fitted in a cool area of the house, for instance in a hallway, and this becomes a point of temperature reference which informs the central heating output throughout the entire house. To work efficiently, the thermostat must be placed where it cannot be affected by a direct heat source, for example, sunlight or a wall heater. From the remote point, the thermostat is wired to the boiler by discreet cabling. The recommended domestic environment temperature is between 18C and 21C. Unless individual radiators are turned off, all rooms occupied or not will be maintained at the reference temperature.
The introduction of a timer into the system can override the thermostat to disable the boiler at certain times during the day, for instance, overnight or when the house is empty during the day.
The incorporation of a timer into a thermostat provides even greater scope for environment control. Modern digital thermostats can be programmed to operate the boiler to maintain various pre-set temperatures throughout the day and on various days. For instance, the programmer may wish the central heating to come on and heat the house to 18C at 7.00 a.m. when they get up, then reduce the temperature to 14C when they leave the house for work at 9.00 a.m. They may also programme the heating to restore the heat level to 18C at 5.00 p.m. when they return from work and reduce it again to 14C when they go to bed at 11.00 p.m. They can also programme different instructions for the weekend and override all settings whenever they wish.
The installation of wireless digital thermostatic programmers enables central heating installers to add controls quickly without the need for extensive wiring. Some modern programmable devices are capable of ‘learning’ about user habits and the environment in which the device is operating. They can be programmed to provide a set temperature at a given time and they then calculate the time at which the boiler should be commanded to operate in order to satisfy the programmer’s request. Eventually, they can formulate a programme based on the user’s preferences and no longer require programming.
Thermostatic radiator valves (TRV) added to radiators enables householders to set individual room temperatures. The valves are easy to install and can be used in any room other than that which incorporates the main thermostatic control device. These devices require no operating power source and work very efficiently by controlling the rate of flow into, and, therefore, the heat output, from the radiator. They are good at regulating temperatures in rooms where extraneous heat sources, like direct sunlight, heat a room at the front or back of the house whilst other shaded rooms are cooler. They do not work efficiently where radiators are housed in screens or when obstructions are placed in front of the thermostats impeding airflow around the device.
Thermostats, which control motorised valves, can regulate the flow of central heating fluid to various areas and rooms in the house. Three-port valves can supply both the central heating and the domestic hot water supply at the same time.
Advances in thermostatic control have led to the development of Remote Energy Management devices that enable householders to set, programme and monitor their heating systems from almost anywhere in the world. The thermostatic device is connected to the home broadband network allowing Wi-Fi access via smartphone, tablet or P.C. by the householder when they are away from home.
As further advances in technology provide greater control over heat and energy management, the opportunity of benefits to consumers will continue to increase.