Net-Zero Buildings : A pathway to comfortable living
As global governments shift towards becoming more decarbonised, Net Zero Energy buildings are becoming more popular among developers. Most countries have set targets to reduce greenhouse gas production and limit climate change impacts to levels where the Earth’s temperature increase will be at or below zero degrees celsius.
In addition to shifting the way we build for Net-Zero Carbon Buildings, in this two-part blog series, we will explore how the the net zero concept is presumed to develop the growth of the building sector in two ways:
A new approach to attain more thermally comfortable building design
A transition in the sources of energy for building operation
Delivering thermal comfort and indoor air quality with net zero buildings:
One of the key requirements to becoming a carbon-neutral building is meeting challenging energy intensity goals. In order to achieve these goals, buildings will need to be naturally ventilated for a substantial proportion of the year, supplemented by mechanical systems to provide heat recovery in winter and comfort cooling in summer.
By carefully designing the façade to improve daylighting, it allows for natural ventilation for longer periods of the year, compared with glazed solutions. Natural ventilation openings in the facade should be designed to allow effective ventilation for a large part of the year. In locations with air quality and/or acoustic concerns, vents should still be included but may not be used from the start. As a future roadmap once the air quality in our towns and cities improves with the use of electric vehicles or hydrogen fuel-based vehicles, these openings will become more frequently used.
The size and depth of the floor plate will have a big impact on the building’s ability for passive daylighting and natural ventilation. Therefore, an ideal design should take this into account, but this is not always possible. In these cases, the interior areas require mechanical ventilation and artificial lighting throughout the year, while the perimeter can benefit from passive measures. There is a lot of potential for using thermal mass to regulate internal temperatures, but it needs to be managed carefully to recharge the mass using night cooling. It must also be considered as part of the broader lifetime carbon rating as concrete, typically used to provide mass, is a high carbon material.
Evaporative cooling through bodies of water and evaporative coolers can help reduce the need for air conditioning during hot and dry periods. It is now possible to use evaporative cooling with conventional air conditioning systems without any difficulty. Ceiling fans have been a popular fixture for many years, and they are now making a comeback in both residential and commercial buildings as well. They are especially effective in the summer because they provide comfort and relief from the heat.
Most new energy efficient buildings incorporate ceiling fans to provide thermal comfort and reduce energy use in cooling. High-efficiency ceiling fans can use only 2 to 30 watts depending on speed settings.
However in colder months, occupant comfort needs to be achieved, by the use of active strategies and technologies. Several other technologies that use the least amount of energy possible to deliver occupant thermal comfort in colder months can include:
Electric floor mats provide targeted, radiant heat to occupants and are only used on the coldest mornings.
Personalized heating/cooling chairs provide occupants with individual thermal controls by delivering heating and cooling directly to their body with only 14 watts in heating mode, and four watts in ventilation mode.
Personal USB heating fans that plug into computers for each occupant. Good airflow enables air temperatures to be four degrees warmer without making occupants uncomfortable.
A net zero energy building will only be cost-effective if all the passive strategies, all of which come at no-cost or low-cost, are incorporated in the planning, design and construction phases of the building.
To learn more: Join Our Event "The Green Real Estate: Beyond Net Zero" on February 9th 2023!
