Sustainable Building Case Study: Conservation House Whare Kaupapa Atawhai

Introduction

Building Outputs

Tennant Outputs

Main Areas of Achievement

Project Background

Environmentally Sustainable Design Considerations

Lessons Learnt

Links

Glossary

Environmentally Sustainable Design Considerations

Management

The Wellington Company and DOC together set out to create an environmentally friendly, energy efficient, sustainable space. They established a project management team that worked collaboratively to maximise the interests of both parties.

Energy

The building uses a number of passive, mechanical and staff behaviour strategies to promote energy efficiency. For example, its mixed-mode ventilation system combines natural ventilation strategies with active chilled beams – an air-conditioning system that significantly reduces energy consumption. It is the first active chilled beam system ever installed in offices in Australasia – a visionary move initiated by building owner, The Wellington Company.

Highly energy efficient, chilled beams are a state-of-the-art sustainable measure being integrated into the design of new and refurbished buildings around the world.

View of the chilled beams, DALI sensor and the highly energy-efficient lights.

Exposed concrete ceiling surfaces act as thermal mass to absorb excess heat generated during the day, and night ventilation flushes the building. Hot water is produced by heat pumps that also capture waste heat from the building.

The high-performance, double-glazed façades not only minimise energy loss and consumption but also allow people to view and understand the natural ventilation and heating.

The lighting system – the Digital Addressable Lighting Interface (DALI) – delivers energy-efficient control of all the building’s lighting, including automatic daylight dimming of perimeter and motion sensor lights. High-efficiency T5 low-mercury lamps and solid-state, long-life LED lamps have been used throughout, minimising not only energy consumption but also the environmental impact of their disposal.

Working in harmony with the DALI lighting controls is a networked building management system that monitors, adjusts and manages the electrical and mechanical systems. This makes it the most sophisticated networked system currently in New Zealand.

The main stairs have also been designed to be visible and easily accessible to encourage staff to use them in preference to the lifts.

A small 1.5 kWh wind generator has been installed on the podium roof to provide power for the lights in the outdoor areas.

The graph on the following page shows the comparison of energy use between a conventional building (on the left) and Conservation House.

The calculations for Conservation House are based on its chilled beams running for 100 per cent of the year. Current predictions are that the chilled beams will only be required for 70 per cent of the year. Based on this prediction, the energy output will reduce to 89+ kWwh/m², resulting in further efficiency and savings.

Water

Rainwater is collected from the building’s roof and walls and stored in a basement tank. This water is supplying 77 per cent of the building’s non-potable demand, such as for cleaning, toilet flushing and servicing the pools on the roof.

Heat pumps provide hot water, and sensor taps conserve water use and energy.

The following graph contrasts the water use per person per day in a conventional building (on the left) with the significant savings made in Conservation House.

Indoor Environmental Quality

The building is naturally ventilated. Fresh air supplied from the rooftop comes down through the atria and returns by convection back to the rooftop through the void between the two layers of external glass.

The use of chilled beams has been shown to increase indoor air quality, as well as reduce plant noise. In fact, background or ‘pink’ noise will feature at Conservation House to counteract the silence of the interior.

The amount of natural light entering the building has been optimised by building atria and installing large perimeter windows. The glass-roofed atria allow natural light to penetrate deeply into the floor plates. The lighting system is designed to react to this natural light and automatically dims individual light fittings to offer a more comfortable and natural working environment.

Building materials were chosen to improve the indoor air quality by specifying materials with low emissions of VOCs and formaldehyde.

Atrium. Photo courtesy of Department of Conservation.

Interior Fit-out

Gill Consultants Ltd, a member of the project management team for the retrofit, commented that employees would not have to use their lungs to filter toxins in the air in this office environment.

Conservation House has a clean, green interior featuring:

• non-toxic paints

• electrical equipment that is free of polychlorines and phenyls

• building materials with low emissions of formaldehyde, chlorofluorocarbons and VOCs.

Timber is from sustainable plantations and includes Tasmanian oak and Victorian ash.

Ecology of the Site

The architects, Architecture+, sought to integrate green building credentials into the streetscape of Wellington by using two glass façades linked to internal atria, allowing the use of natural ventilation in an urban environment.

The Department of Conservation shop on Manners Street provides an active street frontage as well as enhancing the distinctive marketing opportunities of conservation house.

Materials

Building materials were specified that have low emissions of VOCs and formaldehyde to reduce internal air pollutants. Environmental Choice New Zealand products like Laminex MDF, Resene paints and Forbo linoleum were specified wherever possible. Using PVC was avoided where practicable, such as laying linoleum instead of vinyl on bathroom floors.

Waste Minimisation

DOC has moved to full recycling, both at the desk and within the building. Staff have a small bin for recycling waste on their desks, and another bin for recycling paper. The layout of Conservation House allocates space for recycling, so all utility areas and kitchens have separate collection bins for organic, inorganic, paper, glass, plastic and metal waste. Staff are expected to separate their recycling waste from their desk each day.

Network

The highly sophisticated networked building management system monitors, adjusts and manages the lighting, heating, ventilation and air-conditioning systems.

Transport

Conservation House is placed in a central Wellington location and is connected with all the major bus routes in the city. Directly outside the main entry on Manners Street is one of the most well serviced bus stops in the city. Being centred with the central business district of Wellington it is only a short walk to most of the cities major facilities and it is only a 20 minute walk to Wellington railway station. A large bicycle park and shower facilities are located in the building to encourage the use of this sustainable transport option, as well as promoting staff fitness.

Urban Design

The key urban design qualities of this project are:

• context of the site with its maintenance of a strong office and therefore people presence in this part of Wellington

• character in the provision of an active street frontage with interesting Department of Conservation displays that link with the internal aspects of the buildings use

• custodianship in it long term commitment to an environmentally sustainable development

• connections in the high priority placed on walking, cycling and transport due to its central Wellington location.

Roof-top garden outside the café and seminar rooms. Photo courtesy of the Department of Conservation.

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