How can chimneys mitigate overheating in dwellings?10 answersChimneys can play a significant role in mitigating overheating in dwellings by facilitating natural ventilation and reducing heat accumulation. The principle behind using chimneys for cooling is to create a stack effect, where warm air inside the building rises and escapes through the chimney, drawing in cooler air from outside or lower levels of the building to replace it. This natural ventilation method can be particularly effective in enhancing occupant thermal comfort and wellbeing without relying on mechanical cooling, thus reducing greenhouse gas (GHG) emissions associated with energy consumption for air conditioning.
The effectiveness of chimneys in mitigating overheating is influenced by several factors, including the design, construction, and operation of buildings, as well as external climate conditions and occupancy patterns. For instance, the integration of thermal mass and the strategic use of shading can complement the cooling effect provided by chimneys, as thermal mass absorbs heat during the day and releases it at night, while shading devices prevent excessive solar gain.
Moreover, innovative retrofit measures, such as the installation of motor-driven flap valves operated by heating controls in chimneys, can further enhance their efficiency in reducing heat loss and managing indoor temperatures. This approach allows for the controlled ventilation through chimneys, optimizing the stack effect and minimizing overheating risks.
However, it's crucial to consider the occupants' ability to interact with these passive cooling strategies. For example, manual interventions like opening or closing windows or adjusting shading devices in conjunction with chimney ventilation require occupant engagement for optimal performance. Additionally, demographic factors and the specific needs of vulnerable groups, such as the elderly or those with chronic diseases, should be taken into account when designing and implementing chimney-based cooling solutions to ensure accessibility and effectiveness for all inhabitants.
In summary, chimneys can significantly contribute to mitigating overheating in dwellings through natural ventilation and the stack effect, especially when combined with other passive cooling strategies and occupant engagement.
Does a humidifier help to reduce heat stress?5 answersA humidifier can help to reduce heat stress. Recent studies have highlighted the importance of humidity in accounting for extreme values of wet-bulb temperature, which is an indicator of heat stress. Heat stress on humans depends not only on the ambient temperature but also on humidity, wind, and incident radiation. Humidity variations have been found to be more important than temperature in creating extreme heat stress. Irrigation and urban greening, which can increase humidity, have been suggested to exacerbate heat stress. However, the use of different heat stress indices has led to opposite conclusions, making it important to choose the appropriate index. Therefore, a humidifier can be beneficial in reducing heat stress, but it is crucial to consider the specific conditions and choose the right heat stress index.
How does a humidifier help to reduce excessive heat?3 answersA humidifier helps to reduce excessive heat by utilizing different mechanisms. One approach is through heat dissipation. For example, a heat dissipation humidifier LED table lamp uses a water pipe made of a good metal with high heat conductivity to absorb heat from the LED lamp and transfer it to the water in the pipe. The heated water then flows into an evaporation type humidifier, reducing the temperature of the humidifier while also providing humidity. Another method is through heat insulation. A humidifier heat insulation device includes a heat insulation plate that prevents fog from escaping into the water tank, allowing it to be exhausted through a fog outlet. This helps to avoid water overflowing from the humidifier. Additionally, a humidifier based on heat dissipation through convection uses a convection type heat dissipator to dissipate heat from a heating element, allowing for efficient heat reduction. Overall, humidifiers help to reduce excessive heat by either dissipating or insulating it.
How would you build heated pipes?4 answersTo build heated pipes, there are several methods described in the abstracts. One method involves arranging a metal material containing Sn or an Sn alloy and a Cu alloy in a tubular container, heating it to form an inter-metallic compound, bending the container, and then heating it again to form a porous wick structure. Another method involves reducing the diameter of a malleable tube, inserting a smaller tube, crimping and sealing the interface between the two tubes, filling the pipe with a heat transfer fluid, removing air, and sealing the free end of the second tube. A different method uses a single- or multi-channel aluminum profile, pumps out the gas content, introduces refrigerating gas, performs welds along the external surface of the profile, and seals the ends. Yet another method involves mixing organic adhesive with metal powder, molding the mixture, removing the adhesive, sintering the pieces together, and filling and sealing the pipe. Finally, a method involves inserting a mandrel into a tubular body, placing copper powder in a groove, heating calcination, removing the mandrel, vacuum pumping, injecting a working fluid, and sealing the ends.
How can access to water to informal settlement residents be used to mitigate urban heat in cities?2 answersAccess to water for informal settlement residents can be used to mitigate urban heat in cities. Informal settlement dwellers value rivers for providing cool breeze, shades from trees, and recreation, which can help alleviate the effects of heat. Additionally, water-sensitive cities that adopt holistic approaches can counter the health and wellbeing problems associated with urban dryness, which includes heat-related issues. Furthermore, improving water infrastructure resilience in under-served peri-urban and rural areas can contribute to mitigating the impacts of heat on health, sanitation, livelihood, and productivity. It is important to consider the vulnerability and resilience of informal settlement residents to heat-health impacts, as they often have high exposure, high sensitivity, and low adaptive capacity to heat. By incorporating the perspectives of informal settlement dwellers and their use of riverside open and green spaces, urban planners can develop inclusive and sustainable urban development strategies that address the scarcity of open and green spaces and mitigate urban heat.
What is the most cost effective way to heat water?8 answers