Zero energy buildings

By-

Nilesh Dama

Raj Dharod

1. A net zero energy building can be defined as a building in which total

amount of energy used is equal to amount of renewable energy

created on the site2. Means to reduce carbon emissions & reduce dependence on fossil fuels3. Buildings that produce a surplus of energy over the year are called

“Energy Surplus Buildings”

4. During the last 20 years more than 200 reputable projects claiming net zero energy balance have been realized all over the world which extensively utilise the renewable energy sources to earn the tag of ZEB.

What is a Zero Energy Building?

Bayer Material Science building in Greater Noida

Buildings are the Largest Energy Consumer

Components of Zero Energy Buildings

Building's orientation on the site, window and door placement.

Wind Effect Stack Effect Combustion and Ventilation

Plantations On The Roof Insulation on walls and using Light colored roof

Various forms of renewable energy

Solar Energy

• The photovoltaics convert the light energy directly into electric energy by photoelectric effect at the atomic level.

• The solar thermal collectors chosen for this job are flat plate collectors with an efficiency factor of 0.8 and a linear heat loss coefficient factor of 3.5.

Wind Energy

• The total kinetic energy available from wind world-wide is more than 80 times the energy that is being consumed now.

• The wind turbine costs are approximately the same as coal-, natural gas-, and nuclear-based electricity.

Geothermal Energy• The temperature of earth varies

proportionally with depth. We can utilize this temperature to produce limitless energy.

• One percent of the heat contained in just the uppermost 10 kilometers of the earth’s crust is equivalent to 500 times the energy contained in all of the earth's oil and gas resources.

Biogas

• It is the most suitable energy resource as per environmental concern.

• Suitable for rural areas where plenty of organic and inorganic wastes are available, no proper discharging channel is not available.

Comparison

Economical comparison shows that wind energy is most economical amongst all renewable resources mentioned in the graph.

Design Methodology

• Construction & lab experiments are costly• Computer Simulations are convenient &

quick• Very low cost• EnergyPlus and TRNSYS 16.0 are used

• EnergyPlus models hourly energy consumption

• TRNSYS is widely applied for both energy efficiency and renewable energy analyses

• EnergyPlus simulations are used for building envelope design

• TRANSYS is used for building systems and renewable energy systems design

Weather Data Analyses

• Primary step

Wind frequency profile

Yearly wind rose profile Monthly solar radiation distribution profile

EnergyPlus model for domestic house

First floor plan for domestic house

Table 1

Building construction

materials.

Building Elements Material U value (w/square m .C)

External wall Concrete wall & brick 0.4

Glazing 24mm double glazing 1.78

Internal partition Plasterboard & insulation 0.71

Roof construction Concrete tiles 4.298

Cooling load and heating load plots for WWR = 0.1, south orientation.

Cooling load and heating load plots for WWR = 0.1–0.4, U value = 0.1 W/m2 K with different house orientations.

Building systemsSolar hot water system

Parameters

Rated power 165w

Area 1.26 square m

Short circuit current 4.7A

Open circuit voltage 44.2V

Modules 4 * 2

Total rated power 1.32 kW

PV parameters in electricity system

Wind turbine and PV output profile on

kJ/h typical spring day March 21st

The Indira Paryavaran Bhavan.• India’s first net zero energy building

• Constructed with adoption of solar passive design and energy-efficient building materials.

• Building boasts an earthquake-resistant structure with a total plinth area of 31,488 sq. m.

• More than 50 per cent area outside the building is a soft area with plantation and grass.

• The building has a robotic parking system in the basement that can accommodate 330 cars.

• Thin-client networking system has been provided instead of conventional desktop computers

to minimise energy consumption.

• Design allows for 75% of natural daylight to be utilised to reduce energy consumption.

• Installed capacity of 930 kW peak power, the building has the largest rooftop solar system

among multi-storied buildings in India.

• Union environment minister Prakash Javadekar showcased the building to United Nations

secretary general Ban Ki-moon on 13/1/15

• Total energy savings of about 40 per cent through the adoption of energy efficient chilled

beam system of air-conditioning

• Air-conditioning is done by convection currents rather than airflow through air handling

units, and chilled water is circulated right up to the diffuser points unlike the

conventional systems.

• UPVC windows with hermetically sealed double glass. Calcium Silicate ceiling tiles with

high recyclable content and grass paver blocks on pavements and roads, renewable

bamboo jute for door-frame, flyash bricks

• Reduction in water consumption has been achieved by use of low-discharge water

fixtures, recycling of waste water through sewage treatment plant, use of plants with low

water demand in landscaping, use of geothermal cooling for HVAC system, rainwater

harvesting and use of curing compounds during construction.

• Preservation of maximum possible number of trees standing over the site

• Solar Passive Architecture with proper orientation and shading of Fenestrations

• Appropriate building envelope design with envelope insulation to reduce heat intake

• Use of permanent, durable and local materials such as sand stone on exterior face,

low heat transmission glass and reflective roofing

• Priority for pedestrians in the front, with vehicular access on the sides of the building

• Reduction of conventional lighting load by ensuring 75% day-light use

• Natural ventilation due to stack effect

• The building is designed in such a way that there is free ventilation across the entire

building

Architectural design of the building is primarily based on following concepts

• Utilization of High Efficiency Solar Panels to achieve Net Zero criteria

• Energy efficient T-5 and LED fixtures

• Innovative chilled beam system for cooling

• Pre-cooling of fresh air from exhaust using heat recovery wheel in order to reduce load on

chiller plant

• Water cooled chillers

• Double skin air handling units with variable frequency drives

• Geo thermal heat exchange technology used for heat rejection from Air-conditioning

system

• Innovative energy saving regenerative lifts which have been installed for the first time in

government institutional building

Energy Conservation Measures:

Conclusion

• Solar and Wind energy will be the major contributor of renewable energy for ZEB’s owing to their widespread availability.

• Biogas can also be used for our energy needs but its only constraint is that it needs huge quantity of waste and it is also not feasible everywhere.

• Geothermal energy is an upcoming form of energy having great potential to generate electricity but a lot of research still has to be done to tap into its full potential.

THANK YOU