FlexiWarm

Multi-Purpose Heat Pad Stadium Seat Heating Squash Ball Heater 12 Volt Portable Heating 12 Volt: Radiant Heating Systems Apparel 24 Volt: Underfloor Heating

FAQ'S

Q&A Electric Heating Panel

• How does radiant heat compare to convected heat in performance and output
• What are the losses from a room
• What area can you expect the radiant panels to heat up and be effective
• If a room requires 3000Btu heat requirement, how many radiant heaters would be required
• Can the pads operate with 24V or 48V if required
• What is the effect of radiant heat to your health
• What is the expected life of a radiant pad under normal operating conditions
• Do you guarantee the pad against failure and for how long
• If I need to maintain the legal requirements for heat at 21-24 ͦc for an office space how many heaters would be required per M² or M³
• How do I calculate the requirements for a given space
• Will radiant heat source maintain an ambient temperature of 22 ͦ c without any convection
• What is likely to fail on the pad over time
• Can you operate the heating panel with PV Solar, Wind or Batteries
• What size of PV solar panel, wind turbine or battery pack would I need for sustainable performance

Q:How does radiant heat compare to convected heat in performance and output

A:Radiant heat requires less energy input than convected heat, because the air does not need to be warmed.

There are three ways how heat can reach your body: The first is direct contact, for example putting your hands around a cup of hot tea. The second is so-called convection. It means that air becomes warm on the surface of a radiator, then rises and then transports the heat to your body. It is the typical way of heating with most radiators and ovens. The third way is through infrared radiation. Unlike UV light it is a harmless way of radiation. It is similar to visible light, but invisible to the human eye. Basically radiant heat is what makes you feel warm when you stand in the sun. This heat needs no air for transport and no direct body contact. All energy that arrives from the sun is transmitted in this way through space. Visible light and infrared are the same physical phenomenon with the only difference that one can be seen the other only felt.

For heat transmission you need to be in direct contact with the heater, sit on it or lean to it.

For convected heat you have to heat the air first and then keep the air in the room and then you are warmed by the warm air. This is only possible if the radiator (the convector) is quite hot (50-90C), otherwise the air would not transport enough energy to you. The general rule is that hot radiators use more energy than just warm ones. For radiant heat you get the radiation directly to your body or clothing and the temperature of the air is not very important. It works best with a large heated area and temperatures that are around the human body temperature (30-40°C). One result is lower energy consumption because the air does not need heating. The second result is that the comfort is much better if there are no large differences in temperature in the room.

Q: What are the losses from a room.

A:In order to emit a fixed amount of heat energy in a room you need some surface (X) at a temperature of (Y). If the surface is very hot (like in radiators) you will need a small heated surface. If the temperature is lower you need more surface. One example is an underfloor heating system where you have 100% of your floor as heated area. A radiator has only about 0,5-0,7 m², but needs to be much hotter therefore. Essentially you have the choice between "one central unit" (the very hot radiator) or "many smaller units" (the large areas with a temperature like the human body). The performance and the output can be understood very easily: electric energy in a heater is converted into heat. Since there is no chimney, no pipes and such losses, all the energy is turned into heat in the room itself. Gas-fired convector heatings typically lose 35% of the energy on its way from the boiler room to the room you want to heat. As a law of physics a room itself loses heat energy when it is cold outside. How much depends on two factors: one is the insulation of the walls and windows, the second is the temperature of the things in the room. The higher this temperature inside is the more energy gets lost. A hot convection heater that is normally placed along the wall will lose much more energy to the outside than a large panel with moderate warm temperature.

As a result the energy consumed will be less for the same level of satisfaction and comfort if a radiant heater is used.

Q:What area can you expect the radiant panels to heat up and be effective

A:It depends on many factors like insulation of the building, height of the room etc. As a rule of thumb you can assume that a 100 W panel will be good for a volume of 10-15 m³ or an area of 4-6 m² at a room height of 2,5 m.

Q:If a room requires 3000Btu heat requirement, how many radiant heaters would be required

A:Calculate between 170 and 200 W of heating capcaity per 1000 BTU. One standard panel is good for about 500 BTU. 3000 BTU equals about 870 W. Normally this is the capacity of the heater, not the effective consumption. Each of the radiant heaters has a rated output that depends on size and technical specification. Normally about 60-70% of the nominal value will be enough.

Q:Can the pads operate with 24V or 48V if required

A:Yes. In principle the pads can operate with all different voltages, but this requires special planning and wiring as well as matching the power supplies or transformers. Please contact us for more information.

Q:What is the effect of radiant heat to your health

A:Radiant heating is often compared to sunshine. It warms your clothes and skin and therfore the whole body gets warmed. The same can be experienced in an infrared sauna, but temperatures there are higher due to the closed room and the fact that the persons are naked in the sauna. The effect on the body is frequently a relaxation of muscles, a reduction of arthritic pain and other reliefs. Since the temperatures are moderate - like on a summer day or like human body temperature - it is not possible to overheat or burn yourself.

Q:What is the expected life of a radiant pad under normal operating conditions

A:We expect a minimum lifetime of 20-30 years and the components were simulated in a fast aging test. This is double the lifetime of a conventional heater. There are no moveable parts that can break or wear, no pipes that can clog or break. There are also no hot wires that would burn through after some time, nor pipes that could corrode.

Q:Do you guarantee the pad against failure and for how long

A:We guarantee functioning of the pad within the legal regulations. When the heating pad works at arrival there is no reason why it should not work for the next 20 or 30 years, since there are no moveable or wearing parts. Malfunctions can occur only due to wrong treatment, breaking of a contact or overheating of the power supply. Basically the power supply is the only thing that we have ever seen to fail. The reason for it can be wrong use, wrong installation or problems in the electric grid (overvoltage). It can be exchanged relatively easy so that your investment is protected even if this case should occur.

Q:If I need to maintain the legal requirements for heat at 21-24 ͦc for an office space how many heaters would be required per M² or M³

A:This can be answered only based on a detailed calculation. Please supply us with all the relevant informations and data about the project and contact our techncial or sales department. Never forget to factor in the energy consumption of computers, monitors, printers, lighting and other machines. Typically offices have a much lower demand on heating than living rooms but frequently they need air conditioning during summer due to the "passive heating" from office equipment and lighting.

Q:How do I calculate the requirements for a given space

A:Unless you are a heating engineer who is familiar with the national standards for such a calculation you will not be able to calculate it yourself. You may want a professional calculation but this causes additional costs. But you may also opt to use one of the following options to estimate your requirements:

A) presently installed capacity for heating: you may use the nominal capacity of the radiator that is installed in the room at present. This could e.g. be a radiator with 800 or 1200 W. You know yourself if this heater is running on full or not. In most cases it will be enough to have 60-70% of this value installed in electric heating panels.

B) if you know the construction of your house and the heat losses / energy consumption of your room you can use the consumption per year (e.g. 100 kW/sqm for the full year) and divide it by the number of heating hours per year. This will give you a number for the consumption of heat per hour for your room. Obviously you will need at least this capacity in Watt installed, but add sufficient buffer for the cold days.

C) you may use the following table for estimating the heating requirements

Estimate of heating requirements; kWh Heating hours Capacity/hr For 110 m²
  yr/m² Per Year Watts Watts
Old Building, No Insulation 150 3500 43 4714
Renovated, With insulation 100 3000 33 3667
Low-Energy House 60 2500 24 2640
Passive House 20 2500 8 880

 

Q: Will radiant heat source maintain an ambient temperature of 22 ͦ c without any convection

A:No, because there is always a certain amount of convection, unless you are in a vacuum. but the convection will not waste energy, because it will stay in the room. At small temperature differences between heater and room temperature the convection will be rather small. Convection becomes strong only when you have high temperature at the radiator of 50 or 60 °C. When you measure the ambient temperature in a room you basically measure the air temperature. You will find that you will feel warm and more comfortable at a lower air temperature of 18 or 19° instead of 21 or 22°. This is because large temperature differences between walls, windows and radiator cause a lot of convection, raise up dust and make you feel uncomfortable. Experience it yourself.

Q:What is likely to fail on the pad over time

A:When the pad works in the first place, it will normally work for a long time. The heating pad itself has no moving parts, corroding or clogging pipes or anything that can break under normal use. Mechanical stress can cause cables to come lose and break a contact, but this is very unikely if you use the product according to specification. The only thing that has a lower expected lifespan is the power supply, because it is an electrionic unit that can be damaged by overheating, wrong handling or by problems in your power grid (thunderstorms, shorts in the house etc.) We have therefore made sure that the power supply can be replaced in case this incident should occur.

Q:Can you operate the heating panel with PV Solar, Wind or Batteries

A:Yes. If you feed in power from your own solar or wind installation into the grid it is easy to use this power when it is available (net-parallel connection). you just plug the heater into a mains socket and use the power yourself. Or you may sell the energy on the one side to the grid and buy back on the other side. How this is done depends largly on the contract for the feed in in your country.

If you have a stand-alone system ("island grid" or "mini-grid") we recommend to use a battery as a buffer storage and take the power for heating from the battery. It would also be possible to operate directly off PV or mini-windmill, but this means you can heat only when PV or windpower is available. If you have a second heating system that will operate during this time it may still make sense. It may also make sense if you use it as support heating e.g. in greenhouses, sheds, conservatories or mobile homes (including boats).

One big advantage of our heating system is that you can operate it also with 12V DC directly (for 24V and other voltages minor changes are needed). So you don't have to convert 12V DC power from a mini-windmill to 230V AC in order to heat with it. This saves a lot of costs and cuts out the losses that you have when you convert voltages and DC/AC.

Q:What size of PV solar panel, wind turbine or battery pack would I need for sustainable performance (This is a general overview and calculations may vary depending on global location)

A: PV: Theoretically one typical PV panel with 190Wp would provide enough energy for heating two panels with a combined output of 190W. But: this is only possible when the sun shines strong enough (to reach 190W output) and long enough and at the same time when you want to heat. Understandably the consumption for heating must be provided and stored, this means that the weather, temperature and your consumption habits play a big role in the dimensioning. The best way to find out is to define your heating needs first and then give this input to a professional planner of PV installations.

Mini-wind: The situation is similar to the PV, but as a rule of thumb there are 50% more hours with wind per year than there are with sunshine. It means that 100W windmill will generate 50% more power per year than 100W PV.

You can expect more often that the wind is blowing during heating season than sun shining during the heating season. In general it will make more sense to use windmills to power the heating, but again this depends on your climate and your profile of use. Now a combination of the two - PV and wind - is becoming more popular because they compensate each other very nicely. As with PV you should define your heating requirements and let a professional planner work out the best solution for your location and needs.

Battery: It does not matter how the batteries are charged, you can run the heating directly off 12V batteries (24V version and other voltages please check with us). The dimensioning of the batteries is rather simple in principle but may also need a specialist. The batteries must of course contain the amout of energy that you want to take for heating before the battery is recharged again. Depending on the type of battery a deep- discharge protection (electronic) may be needed to extend the lifetime of the battery. Also for this point consult a specialist. Most sellers of PV and mini-windmills but also many from the car- and camping industry will be able to offer the right products and assist in the dimensioning.