The term “thermal insulation” refers to a material that aids in the reduction of heat transmission between objects in thermal contact or within the range of radiative effect. These materials are used all around to prevent heat from exiting or entering rooms or objects, as well as to safeguard combustible goods from excessive heat.
Buildings and vehicles such as trains and aircraft can save money by insulating against heat exchange. Thermal insulation also guards against changes in the physical and chemical properties of adjacent items, which can result in damage and injury.
Any method of lowering the strength of sound concerning a certain source and receptor is referred to as acoustic insulation. It contributes to the reduction of noise that enters, exits, or moves across a room or place. Unwanted or excessive noise can cause distraction, migraines, and, in extreme circumstances, hearing loss.
When a room is soundproofed, sound waves are absorbed by a porous material such as foam or sponge, which reduces direct sound, echoes, and reverberation.
Difference Between Thermal Insulation and Acoustic Insulation
Thermal insulation prevents heat transfer, while acoustic insulation prevents sound transmission or reverberation. The resulting product is thermal acoustic insulation, which reduces both heat and noise transfer.
Thermal insulation acts as a barrier to prevent heat transfer. In the winter, a lot of heat is generated within the house, which is maintained through adequate insulation. When the thermostat detects that the house has achieved the desired temperature, the heater is immediately turned off.
Warmth escapes without insulation. Thus, the heater must keep producing heat to maintain the target temperature.
The role in the summer is opposite compared to that of winter. The heat is then sent to the exterior, where the same insulation prevents much of it from entering the house. This eliminates the need for air conditioners to run continuously.
Internal wall insulation is now almost expected rather than optional, especially near theatres, where current sound systems may readily be heard throughout the house. Internal wall insulation can be used with a comprehensive climate control system to direct heating and cooling energy where it is most required.
How Heat is Transmitted in Thermal Insulation and Acoustic Insulation
Conduction: It is the transfer of heat from one molecule inside material to another or from one material to another when they come in direct contact. Solids and liquids, where the particles are closer together, conduct heat more readily than gases, where the particles are more apart.
Convection: It is the transmission of heat from one medium to another, such as air or water. Convection currents are the air currents that are formed within a place. Convection (or convective heat transfer) is the flow of fluid that allows heat to be transferred from one location to another. In liquids and gases, convection is the most common mode of heat transmission. Other than buoyancy forces, convection can be “driven” by fluid flow (for example, a water pump in an automobile engine). Convection can also be induced by the thermal expansion of fluids.
Radiation: Heat is transported in a wave motion, similar to how light is communicated. Heat is transferred through radiation in the form of electromagnetic waves, which are most visible in the infrared spectrum. The heat agitation of a body’s constituent components causes it to emit radiation.
Acoustic and Thermal Insulation in Electric Vehicles
Electric vehicle sales are progressively gaining traction in various regional markets, but they are still insignificant when compared to the global market for internal combustion engine vehicles.
As different estimates indicate that electric vehicles would eventually dominate the automobile industry, several established vehicle manufacturers, as well as a few newcomers, have begun to align their businesses’ aims to produce electric vehicles.
The rising demand for various insulation materials such as foams, fibers, and rubber pads has resulted from the expanding application areas for insulation in electric vehicles. Automobile manufacturers have invested in providing enough insulation in their electric vehicles to improve the driving experience, which is expected to lead to an increase in electric vehicle sales.
Noise Issue in Electric Vehicles
Changes in a vehicle’s noise, vibration, and harshness (NVH) qualities have become a serious issue since the introduction of EVs. Electric vehicles are noticeably quieter than vehicles with internal combustion engines, owing to the lack of noise caused by the gasoline engine and transmission systems.
As a result, EVs can glide along the road without making any noise or polluting the air. Although an EV’s sound is significantly reduced, there are now various ancillary noises that are common in electric vehicles.
In the absence of engine noise, these noises that were previously muffled out in an internal combustion engine vehicle are now audible. While driving, an electric car makes various new noises, including whining from the powertrain and the electric motor, as well as tire and external aerodynamic noises. In an electric car, noises like buzz, squeak, and rattle (BSR) become more noticeable.
Such supplementary noises detract from the driving experience by interfering with the acoustics from sound systems or haptic input. Acoustic insulation in an electric car is critical in these circumstances.
The acoustic insulation performance in EVs needs to be improved to prevent noises from both within and outside the vehicle, such as the vehicle Heating, Ventilation, and Air Conditioning (HVAC) system and the vehicle electric drive system, from entering the passenger cabin.