Solar energy has gained slow but steady growth in use over the 20th century and in this new century has seen a rapid expansion as the increasingly obvious environmental impacts of Global Warming make adopting sustainable technology a critical necessity. Utilihab favors the use of solar energy systems wherever possible and in particular favors the use of active system that can realize economy through modularization and can work effectively in a large variety of situations.
Passive solar thermal systems represent the oldest, simplest, and most reliable approach to the domestic use of solar energy and are typified by architectural designs focused on the exploitation of passive solar insolation. However, in practice passive solar energy has seen unpredictable performance, frankly, because practitioners of passive solar design have highly variable knowledge, employ variable diligence, and must cope with great variation in both the design of dwellings and the characteristics of the site environments they are in. Passive solar systems rely on balancing, through the form and composition of a structure, the characteristics of solar gain (usually through window position and area), insulation, and thermal capacitance -or thermal mass. (usually through the employ of high mass building materials like earth and earth block) Since these thermal characteristics become integral to the structure -and often rely on building methods using high mass materials that are not easily modified- it becomes very difficult to tune the performance of passive solar structures or correct very glaring mistakes. Perhaps only half of passive solar homes built perform close to as expected.
Utilihab favors employing passive solar design but considers it secondary to the ideal of adaptive architecture, favoring the approach of actively tuning the energy performance of a structure through that adaptability. It has a limitation in passive solar performance in that, based on light high-performance building materials, it lacks large passive thermal mass volume. And so it generally favors modular active solar energy systems that can be positioned and scaled independently of the habitable structure as a way to tune its solar performance. In this section we will explore some of the more common forms of active solar thermal systems used with Utilihab.
Solar Thermal systems are systems based on exploiting solar insolation for its heat energy -as opposed to photovoltaics that convert the solar energy into electricity. Though some domestic solar schemes rely entirely on solar-electric systems, it is more practical to combine solar thermal and solar electric technology as the conversion of electricity to heat is inefficient and loses much the solar potential. Passive solar systems are based on heating ambient air. Active solar thermal systems are mostly based on heating water, supplementing or replacing other forms of energy for heating hot water used in washing, bathing, and radiant hydronic room heating. Most of the Utilihab solar thermal systems are designed for integration to the Utilihab Modular Hydronic Heating and Mini-Duct High Velocity HVAC systems and can function in supplementary, hybrid, or primary heating -and cooling- roles.