DESIGNING THE HEATING SYSTEM
Sizing a heat pump correctly is vital for optimum performance as it is necessary to ensure efficiency and reliability. Under sizing a heat pump will lead to a lack of comfort and high running costs, whereas over sizing a heat pump will lead to short cycling and early failure of components.
Matrix Energy Systems are a national industry leading energy assessment company that specialise in sizing renewable technology form heat pumps to biomass boilers.
Matrix Energy Systems advise that it is imperative that a heat load calculation be completed before any choices are made with respect to the type of heating system to be used. The heat load calculation will show not only the total heat loss of the building but also the individual room by room heat demands; this will allow the correct choice of radiators or under-floor heating and also to select the correct type and output of heat pump that will be fit for purpose.
Hindhaugh Homes take great care from concept to completion to ensure that every aspect of each project is completed professionally; the heat load calculation is a primary building block for ensuring the comfort and efficiency of every completed project for our customers.
AIR TIGHTNESS & VENTILATION
Air tightness is an increasingly important part of the ‘whole house’ approach to building. Air tight buildings will be more comfortable for occupants and also more energy efficient.
As a first step to providing effective, controllable and energy efficient ventilation, air leakage must be minimised.
Air tightness needs to be a priority throughout the construction process – before, during and after.
Too much air leakage leads to unnecessary heat loss and discomfort from cold draughts and in some cases can cause condensation.
Warm air leaking out of the gaps is a major cause of heat loss and consequently wasted energy.
Improving air tightness in dwellings will reduce air leakage, the uncontrolled flow of air through gaps in the building fabric (draughts) should not be confused with ventilation.
Controlling ventilation via built in ventilators is necessary for a comfortable and healthy environment, commonly situated in kitchens and bathrooms to reduce humidity levels.
Build tight – ventilate right
The main purpose of insulation is to create a barrier around the building, that is, over the roof, on the walls, and beneath the floor, which reduces the amount of heat entering the home on a warm day, and reducing the amount of heat loss on a cold day.
Since the majority of heat is lost or gained through the roof and the exposed walls, these areas are the most fundamental places to insulate in order to create a comfortable and energy efficient home.
Eighty percent of energy used in homes is for heating.
Our aim is to over-specify insulation levels in all areas of the house from walls, floors, ceilings to doors and windows.
HOW DOES A HEAT PUMP WORK?
Every house has a heat pump in the kitchen……………it’s your fridge!
It uses a refrigerant to extract energy from the food we put in them. If you have ever put your hand on the back of a fridge, it will feel warm. That’s the by-product of a fridge after the energy from the food has been compressed. Once this warmth is given off the refrigerant becomes cold again ready to absorb more heat energy from more food. The longer the heat pump in the fridge runs, the colder the fridge will get, in fact cold enough to freeze things.
A heat pump we use for giving us heating and hot water works in the same way but instead of food, it uses a refrigerant to extract energy (heat) from an energy source such as the air around us, the ground and water in or on the ground. All this energy is trapped solar energy from the sun, the earth’s power source.
For an Air Source Heat Pump, the outdoor air is sucked into the heat pump. The fan then routes the air to the heat pump’s evaporator. Here, the air releases the heat energy to the refrigerant and the air’s temperature drops. The cold air is then blown out of the heat pump.
For a Ground Source Heat Pump, a special fluid is pumped in pipes which are placed in the ground.
These pipes can either be laid in a trench or down a bore hole.
This fluid picks up energy and brings it back to the heat pump’s evaporator. The fluid releases the heat energy to the refrigerant and the fluid’s temperature drops. The cold fluid is then pumped from the heat pump back to the ground to pick up more energy.
So the refrigerant is the key to the whole thing!!
Here’s the science bit…………..
The refrigerant is a liquid gas which circulates in a closed system in the heat pump. The refrigerant has a very low boiling point. In the evaporator the refrigerant liquid receives the heat energy from the outdoor air, or the ground and starts to boil into a gas.
The gas that is produced during boiling is routed into an electrically powered compressor. When the gas is compressed, the pressure increases and the gas temperature increases considerably, for example from 5 °C to approx. 80°C.
Have you ever put your thumb over the end of a bike pump are pumped the handle. Your thumb gets hot, you are the compressor and the air is the gas.
From the compressor, gas is forced into a heat exchanger, the condenser, where it releases heat energy to the heating system in the house, whereupon the gas is cooled and condenses to a liquid form again.
As the pressure is still high, the refrigerant can pass an expansion valve, where the pressure drops so that the refrigerant returns to its original temperature. The refrigerant has now completed a full cycle. It is routed to the evaporator again and the process is repeated.
The heat energy that the refrigerant produces in the condenser is retrieved by the heating system’s water, which is heated to 65°C to then be pumped to the heating system and hot water tank.
BENEFITS OF UNDERFLOOR HEATING
Underfloor heating is arguably superior to conventional methods for various reasons. Some of the more noticeable benefits of underfloor heating include comfortable heat, energy efficiency, aesthetics, and the silent operation of underfloor heating.
With conventional heating, air rises to the ceiling and warms the upper body while leaving the lower body cooler. In contrast, underfloor heating warms the lower part of the room and the body. When the air rises from the floor, it loses heat and gives off a feeling of natural warmth. Underfloor heating is installed close to the floor surface resulting in a quick warm up of the room. The heat is spread over the entire floor, reducing the heat loss from our bodies without overheating the surrounding area. Underfloor heating gently and evenly warms in the same way as the sun, providing warmth without the stuffiness of conventional heating systems.
In addition to providing more comfortable heating, underfloor heating also provides healthier heating. Underfloor heating is buried under the floor and since the entire floor acts as one huge radiator, there are no hot spots to create large air currents that carry dust particles around the room. Underfloor heating causes less air movement, thereby causing minimal circulation of pollution, dust, and allergens throughout the room. It is less likely to dry out your breathing passages and skin.
The uniform heat distribution from underfloor heating makes it possible to set the thermostat 2 – 4 degrees lower than usual without any loss of comfort or warmth. The underfloor heating system is very efficient because it provides a lower air temperature allowing you to feel warmer at a lower temperature because the underfloor heating is lowering the heat loss from your body. Underfloor heating concentrates the heat in the lower half of the room where the human body needs it most. Energy savings will vary depending on the insulation and usage pattern of the underfloor heating system, but you can save anywhere from 10-40% on energy costs.
In summary, underfloor heating is comfortable, healthy, aesthetic, space saving, silent, and energy efficient.
MCS ACCREDITED INSTALLER & RHI GRANTS
Hindhaugh Homes uses HT Energy to design and install all work at present. HT Energy are multiple award winning installers, who won the national award for ‘Best Heat Pump installation 2012’ for our development at Newton Hall..
HT Energy supply a 5 years parts and labour warranty for all our developments which they are involved with.
They are MCS accredited which allows the properties to benefit from the RHI ( Renewable Heat Incentive) grant.