Trombe wall is a passive solar building design strategy that adopts the concept of indirect-gain, where sunlight first strikes a solar energy collection surface, thermal mass, which is located between the sun and the space. The sunlight absorbed by the mass is converted to thermal energy (heat) and then transferred into the living space. Trombe walls are also distinguished as mass wall, solar wall, or thermal storage wall. However, due to the extensive work of professor Félix Trombe and architect Jacques Michel in the design of passively heated and cooled solar structure, they are often called Trombe Walls. This system is similar to the air heater created by professor Edward S. Morse a hundred years ago. The basic principle of Trombe wall system is that thermally massive south-facing walls are painted to a heat absorbing dark color and covered with a glass on the outside, leaving an air gap between the wall and the glaze.
In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unlike active solar heating systems, it does not involve the use of mechanical and electrical devices.
In building design, thermal mass is a property of the mass of a building which enables it to store heat, providing "inertia" against temperature fluctuations. It is sometimes known as the thermal flywheel effect. For example, when outside temperatures are fluctuating throughout the day, a large thermal mass within the insulated portion of a house can serve to "flatten out" the daily temperature fluctuations, since the thermal mass will absorb thermal energy when the surroundings are higher in temperature than the mass, and give thermal energy back when the surroundings are cooler, without reaching thermal equilibrium. This is distinct from a material's insulative value, which reduces a building's thermal conductivity, allowing it to be heated or cooled relatively separate from the outside, or even just retain the occupants' thermal energy longer.
Solar thermal energy (STE) is a form of energy and a technology for harnessing solar energy to generate thermal energy or electrical energy for use in industry, and in the residential and commercial sectors.
A solar chimney – often referred to as a thermal chimney – is a way of improving the natural ventilation of buildings by using convection of air heated by passive solar energy. A simple description of a solar chimney is that of a vertical shaft utilizing solar energy to enhance the natural stack ventilation through a building.
A solar thermal collector collects heat by absorbing sunlight. The term "solar collector" commonly refers to a device for solar hot water heating, but may refer to large power generating installations such as solar parabolic troughs and solar towers or non water heating devices such as solar air heaters.
Electric heating is a process in which electrical energy is converted to heat energy. Common applications include space heating, cooking, water heating and industrial processes. An electric heater is an electrical device that converts an electric current into heat. The heating element inside every electric heater is an electrical resistor, and works on the principle of Joule heating: an electric current passing through a resistor will convert that electrical energy into heat energy. Most modern electric heating devices use nichrome wire as the active element; the heating element, depicted on the right, uses nichrome wire supported by ceramic insulators.
Renewable heat is an application of renewable energy and it refers to the renewable generation of heat, rather than electrical power. Renewable heat technologies include renewable biofuels, solar heating, geothermal heating, heat pumps and heat exchangers to recover lost heat. Significant attention is also applied to insulation.
Underfloor heating and cooling is a form of central heating and cooling which achieves indoor climate control for thermal comfort using conduction, radiation and convection. The terms radiant heating and radiant cooling are commonly used to describe this approach because radiation is responsible for a significant portion of the resulting thermal comfort but this usage is technically correct only when radiation composes more than 50% of the heat exchange between the floor and the rest of the space.
Solar air conditioning refers to any air conditioning (cooling) system that uses solar power.
Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or no energy consumption. This approach works either by preventing heat from entering the interior or by removing heat from the building. Natural cooling utilizes on-site energy, available from the natural environment, combined with the architectural design of building components, rather than mechanical systems to dissipate heat. Therefore, natural cooling depends not only on the architectural design of the building but on how the site's natural resources are used as heat sinks. Examples of on-site heat sinks are the upper atmosphere, the outdoor air (wind), and the earth/soil.
An absorption heat pump is an air-source heat pump driven not by electricity, but by a heat source such as solar-heated water, or geothermal-heated water. Absorption refrigerators also work on the same principle, but are not reversible and cannot serve as a heat source.
Building insulation is any object in a building used as insulation for any purpose. While the majority of insulation in buildings is for thermal purposes, the term also applies to acoustic insulation, fire insulation, and impact insulation. Often an insulation material will be chosen for its ability to perform several of these functions at once.
Solar gain is the increase in thermal energy of a space, object or structure as it absorbs incident solar radiation. The amount of solar gain a space experiences is a function of the total incident solar irradiance and of the ability of any intervening material to transmit or resist the radiation.
A solar combisystem provides both solar space heating and cooling as well as hot water from a common array of solar thermal collectors, usually backed up by an auxiliary non-solar heat source.
Annualized geo-solar (AGS) enables passive solar heating in even cold, foggy north temperate areas. It uses the ground under or around a building as thermal mass to heat and cool the building. After a designed, conductive thermal lag of 6 months the heat is returned to, or removed from, the inhabited spaces of the building. In hot climates, exposing the collector to the frigid night sky in winter can cool the building in summer.
HVAC is a major subdiscipline of mechanical engineering. The goal of HVAC design is to balance indoor environmental comfort with other factors such as installation cost, ease of maintenance, and energy efficiency. The discipline of HVAC includes a large number of specialized terms and acronyms, many of which are summarized in this glossary.
Solar air heating is a solar thermal technology in which the energy from the sun, insolation, is captured by an absorbing medium and used to heat air. Solar air heating is a renewable energy heating technology used to heat or condition air for buildings or process heat applications. It is typically the most cost-effective out of all the solar technologies, especially in commercial and industrial applications, and it addresses the largest usage of building energy in heating climates, which is space heating and industrial process heating.
With all solar thermal collector systems there is a potential risk that the solar collector may reach an equilibrium or stagnation temperature higher than the maximum safe operating temperature. Various measures are taken for optical overheating protection.
Radiant heating and cooling systems are temperature-controlled surfaces that exchange heat with their surrounding environment through convection and radiation. By definition, in radiant heating and cooling systems, thermal radiation covers more than 50% of heat exchange within the space. Hydronic radiant heating and cooling systems are water-based. It refers to panels or embedded building components. Other types include air-based and electrical systems. Important portions of building surfaces are usually required for the radiant exchange.
