Design of Net Zero Energy House in Ahmedabad

Design of Net Zero Energy House in Ahmedabad

Project Year: 2011-12

Funding Agency: WinBuilt

With increasing energy consumptions in the country the need of the day is to build energy efficient homes. This project aims at building a Net Zero energy home. The proposed project is an individual home of 200 m2 built up area in a residential community, KESAR residential building project site, on Sanand road near Ahmadabad. The aim of this report is to identify, various technologies that could be used to build a net zero home.  Energy simulations have been performed over conventional building and various Energy Conservation Measures (ECMs) have been simulated to achieve an optimal solution for achieving a net zero home.

A yearlong monitoring is proposed to be done in two identical homes, one with conventional construction practices and other is the proposed net zero home.  Both the homes would be fitted with instruments and monitored to study overall building performance and actual energy savings. This measurement and verification process will play an important role in evaluating and understanding the performance of net zero building solutions in terms of overall building and the systems performance in real dynamic weather conditions.

R&D organisation and academic institutions

IIIT Hyderabad

Project Outcomes:

• Net zero energy building
• The total energy consumption of the base model 9.556 MWh per year, whereas the total energy product from the solar PVs is only 6 MWh per year. The base model chillers consumes 47% of the total energy use. This gives us an opportunity to improve the energy efficiency of the building through envelope modifications.
• Also the lighting load has been reduced by the use of daylight sensors, and the HVAC equipment chosen has a higher CoP value which will ensure a reduction in the chiller energy consumption.
• The Monthly savings achieved over the base case model has been shown below:

The type of envelope and the shading used in the design are

Envelope details
Component	# of layer	Layer name	Thickness	Property
Wall	2	Aerated Concrete Slab	200 mm	U value – 0.395 W/m2 K
		Insulation	40 mm
Roof	3	Cool Roof	10 mm	SR – 0.7, TE – 0.9, U – Value 1.048 W/m2 K
		Concrete	200 mm
		Insulation	25 mm
Floor	4	Ceramic tile	30 mm	U value – 0.884 W/m2 K
		Floor screed	70 mm
		Concrete	100 mm
		Insulation	25 mm
Window glass	3	Clear glass	6 mm	VLT – 0.25, SHGC – 0.3, U value – 1.658 W/m2 K
		Air gap	30 mm
		Clear glass	6 mm
Infiltration 0.5 ac/hr

Shading
Type	Name	Position	Length
Window shading	Blinds with low reflectivity slats	Mid pane	25 mm
Local Shading	Louvers	Outside	300 mm blades with 15o tilt
	Projections	Outside	300 mm
	Overhangs	Outside	300 mm

HVAC
System type	CoP
VRV system	5.0

In certain months the energy generated by the solar photovoltaic system reach a surplus state and the certain months it is deficit. This has also been studies to understand when do we have to buy energy from the grid and the when we can export it.

The results are presented below;