SECTION 5 - ENERGY EFFICIENCY

Question 17

The project

Illustrated over page is a proposed library for construction in Orange NSW. The building is to be constructed on a sloping site and will contain 2 storeys. The upper storey will have pedestrian access from the street via its entry. The lower storey (a carpark) will have pedestrian and vehicle access from outside. The building has overall floor plan dimensions as shown.

The external walls to the upper storey and the internal upper storey walls surrounding the stairway are proposed to be constructed using precast reinforced concrete panels 125mm thick. These walls will be lined internally with 10mm thick plasterboard on steel furring channels (40mm deep). Internal walls on the upper storey will be steel framed walls lined with plasterboard. Lower storey walls will be reinforced concrete block walls 200mm thick.

The roof comprises steel trusses (20 degree pitch) with a plasterboard ceiling affixed on battens to the underside, and a colour bonded steel roof covering affixed atop metal purlins. The roof will be ventilated. The roof covering will have an upper surface solar absorptance value of not more than 0.4. Eave width is shown on the sections.

Floors will be reinforced concrete. The suspended floor over the lower storey carpark will be 150mm thick.

Glazing

It is proposed that glazing in external walls (ie windows and glazed doors) be of double pane clear glass in thermally improved aluminium frames with a SHGC of

0.36 and a Total System U-Value of 4.4. Other than the glass doors the glazing will be fixed.

Lighting

All internal spaces will have recessed fluorescent lights installed throughout.

Daylight sensors and a dynamic control device for lights within the library general area adjacent to windows W1, W2 and W3 for a distance from the windows equal to the depth of the floor to window head height will be used.

The stack shelf area will have a manual dimming system.

Air-conditioning and ventilation

The upper storey will be heated and cooled by a low pressure air-cooled direct expansion package unit air-conditioning and mechanical system of 25kWr capacity. The air-conditioning air-flow rate is 1650L/s and the sensible heat load is 120W/m2.

The air-conditioning damper (not motorized) requires that minimum performance filters are to be installed and as a consequence the entrance air supply rate will be 200L/s. The air-conditioning unit will be on the roof. Flexible ductwork will be used to connect the main ductwork to each service outlet. The flexible ductwork will not exceed 4m in length. Some of the ductwork and fittings will be exposed on the roof. All other ductwork will be located in the roof void.

The mechanical ventilation serving the amenities will have an air-flow rate of 100L/s.

The air-conditioning and mechanical ventilation system designer will provide for three thermal zones, one for the parts facing south and two for the library general area due to the size of the space.

Based on this information, and the information in the drawings, provide answers to the following -

(a)In relation to the opaque building elements that are a part of the envelope

determine:

(i)The minimum Total R-Value that each must have

(ii)Whether or not insulation must be added to the element to achieve therequired minimum Total R-Value, and if yes, what R-Value the addedinsulation must possess. State 'nil' if you determine no insulation mustbe added.

Present your responses in the following tabular format:

(b)Using the ABCB’s facade calculator assess the proposed glazing for compliance with the DTS Provisions of Part J1.

Assess glazed elements in numerical order. Do not include windowsoutside of the conditioned space (see project description).

If non-compliant glazing is encountered indicate a possible compliancesolution (in general terms).

(c)In relation to the proposed air-conditioning and mechanical ventilationsystem and features it must possess to enable it to use energy efficiently, specify the operational controls required.