Building Energy Conservation Topics: Technical Approach

1. Architectural planning and design

In the face of global energy and environmental problems, many new design concepts have emerged, such as micro-row buildings, low-energy buildings, zero-energy buildings and green buildings.

In essence, they all require architects to start from an overall comprehensive design concept and insist on working closely with energy analysis experts, environmental experts, equipment engineers and structural engineers.

In architectural planning and design, according to the influence of a wide range of climatic conditions, according to the specific environmental climatic characteristics of the building itself, it is important to use the natural environment (such as external airflow, rainwater, lakes and greening, terrain, etc.) to create a good building indoor micro climate to minimize reliance on construction equipment.

The specific measures can be summarized into the following three aspects:

• Reasonably choose the address of the building and adopt a reasonable external environment design.

The main method is: arranging trees, vegetation, water surface, rockery, and walls around the building.

• Reasonably design the building shape (including the determination of the overall building volume and building orientation) to improve the existing microclimate.
• Reasonable architectural form design: Make full use of the outdoor micro-environment of the building to improve the key parts of the indoor micro-environment of the building, mainly through the structural design of the building components and the reasonable separation design of the interior space of the building.

At the same time, the optimization design can be carried out with the help of relevant software, such as the use of building shadow simulation in Tianzheng Architecture (II) to assist in the design of building orientation and roads, greening, outdoor leisure space in residential quarters, and the use of CFD software.

Such as: PHOENICS, Fluent, etc., to analyze whether the indoor and outdoor air flow is smooth.

2. Enclosure structure

The design of building envelope components (roofs, walls, foundations, insulation, sealing materials, doors and windows, shading) has implications for building energy consumption, environmental performance, indoor air quality and the visual and thermal comfort of users have a fundamental impact.

Generally, the cost of increasing the envelope structure is only 3% to 6% of the total investment, while the energy saving can reach 20% to 40%.

By improving the thermal performance of the building envelope, it can reduce the introduction of outdoor heat into the room in summer, and reduce the loss of indoor heat in winter, so that the thermal environment of the building can be improved, thereby reducing the cooling and heat consumption of the building.

First of all, improving the thermal performance of each component of the envelope structure is generally implemented by changing the thermal performance of its constituent materials, such as the thermal diode wall newly developed by the European Union (low-cost sheet thermal diodes only allow heat transfer in one direction, can produce thermal insulation effect) and the thermal performance of the glass changes dynamically with the seasons.

Then, according to the local climate, the location and orientation of the building, and guided by the calculation results of the building energy consumption software DOE-2.0, the optimal design method of the envelope structure combination is selected.

Finally, evaluate the technical and economic feasibility of each component and combination of the envelope to determine a technically feasible and economically reasonable envelope.

3. Improve the energy efficiency of end users

The energy-efficient heating and air-conditioning system and the above-mentioned measures to reduce indoor cooling and heating loads can truly reduce the energy consumption of heating and air-conditioning.

First, design an energy-efficient HVAC equipment system based on the characteristics and functions of the building.

For example: heat pump systems, energy storage systems and district heating, cooling systems, etc.

Then, energy management and monitoring systems are used to monitor and regulate indoor comfort, indoor air quality and energy consumption during use.

For example, European countries measure the temperature, humidity and sunshine intensity of the surrounding environment through sensors, and then predict the heating and air-conditioning load based on the building dynamic model to control the operation of the HVAC system.

In other home appliances and office equipment, energy-saving certified products should be used as much as possible.

For example, the United States generally encourages the use of “Energy Star” products, while Australia implements Minimum Energy Performance Standards (MEPS) for energy-intensive home appliances.

4. Improve the overall energy utilization efficiency

Energy losses are significant during the transition from primary energy to final energy used by building equipment systems.

Therefore, the evaluation should be carried out from the whole process (including extraction, processing, transportation, storage, distribution and end-use) in order to fully reflect the energy utilization efficiency and the impact of energy on the environment.

Energy-consuming equipment in buildings, such as air conditioners, water heaters, washing machines, etc., should use energy-efficient energy supplies.

For example, as a fuel, natural gas is more overall energy efficient than electricity.

The second-generation energy system can make full use of different grades of thermal energy to maximize energy utilization efficiency, such as combined heat and power (CHP), combined cooling, heat and power (CCHP).

5. Utilize new energy

The utilization of new energy plays a vital role in saving energy and protecting the environment.

New energy usually refers to unconventional renewable energy, including solar energy, geothermal energy, wind energy, biomass energy, etc.

People have carried out extensive exploration on various solar energy utilization methods, and gradually clarified the development direction, so that solar energy can be used initially, such as:

(1) As an important project in the utilization of solar energy, the solar thermal power generation technology is relatively mature. The United States, Israel, Australia and other countries have invested in the construction of a number of experimental solar thermal power generation stations, and it is expected to realize the commercialization of solar thermal power generation in the future.

(2) With the development of solar photovoltaic power generation, many photovoltaic power stations and “sun roof” demonstration projects have been built abroad, which will promote the rapid development of grid-connected power generation systems.

(3) There are tens of thousands of photovoltaic water pumps operating all over the world.

(4) The technology of solar water heater is relatively mature and has corresponding technical standards and specifications, but it is still necessary to further improve the function of solar water heater and strengthen the construction of solar energy building integration.

(5) Passive solar buildings have been widely used because of their simple structure and low cost. The design technology is relatively mature, and there are design manuals for reference.

(6) The solar absorption refrigeration technology appeared earlier and has been applied in the field of large air conditioners; the solar absorption refrigeration is in the stage of prototype development and experimental research.

(7) Solar drying and solar cookers have been popularized and applied to a certain extent.

However, in general, the scale of solar energy utilization is not large, the technology is not perfect, and the degree of commercialization is low, and further research is still needed.

When using geothermal energy, on the one hand, high-temperature geothermal energy can be used to generate electricity or directly for heating and hot water supply.

On the other hand, low-temperature geothermal energy can be utilized by means of ground source heat pumps and tunnel wind systems.

Wind power generation is more suitable for windy coastline mountainous areas and high-rise buildings that are prone to strong winds. There have been successful engineering examples in the United Kingdom and Hong Kong, but in the field of construction, the more common form of wind energy utilization is natural ventilation.