Adapt/Survive: Practices and Methods. & Conservation Policies. Outside the Box Energy. Slide 1

Transcription

1 Practices and Methods Slide 1 Adapt/Survive: Outside the Box Energy & Conservation Policies Mick Newnham : National Film & Sound Archive of Australia 1

2 Slide 2 Svante Arrhenius 2 Svante Arrhenius ( ) demonstrated the relationship between temperature and rate reaction. Effectively giving us the box we work with.

3 Slide 3 Arrhenius equation k = Ae -E a /(RT) 3 The Arrhenius equation shows the temperature / rate relationship. I m not going to go through it, you can look it up if you are interested.

4 Slide 4 environment macroclimate microclimate 4 Need to think holistically about vaults and what the building needs to do Methodology from the outside in start with local environment/climate data obtainable from the weather bureau consider the buffering effects of the building/macroclimate - some basic engineering equations determine any benefit from microclimate control - what still needs to be done?

5 Slide 5 5 Case study An existing building made from traditional materials Collection profile - magnetic tape

6 Slide 6 Tropic of Cancer Guelatao 6 Location, tropical but high altitude and more temperate

7 Slide Tropic of Cancer Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Guelatao 7 ~20 o C max min variation over the year but steady annually (~5 o C)

8 Slide 8 Tropic of Cancer Guelatao adobe comparatively poor insulation (dependent on moisture content) high thermal mass (buffer temperature change) 8 Adobe construction, in a lower storey location in a larger building (provides some insulation from above) Diurnal changes buffered by adobe to provide a stable temperature all year (~17-18 o C anecdote/assumption no dataloggers) RH is uncontrolled and unknown but would closely reflect external changes, no data available for Guelatao. Rely on other indicators such as mould, none present including behind shelving, under flooring, assumption RH<60% Recommendation to look at passive RH microclimate controls for the exclusively magnetic tape collection. Slide 9

9 9 Case study, repurposed older building Collection profile - magnetic tape plus some documentation and artefacts

10 Slide 10 Roebourne Tropic of Capricorn 10 Location, tropical but hot and comparatively dry compared to Guelatao

11 Slide 11 Roebourne Tropic of Capricorn 102 o F 11 ~15 o C diurnal range and ~ 10 o C over the year

12 Slide 12 Roebourne Tropic of Capricorn fibro R 0.9 (US R 5.1) 12 Fibro = fibre cement sheeting ubiquitous building material, lightweight with low thermal mass & low R rating - barely more than the air to surface interface (called air film ) on the internal and external surfaces ~R 0.18

13 Slide 13 the ideal reflected heat heat energy reflective external coating external cladding moisture membrane bulk insulation thermal mass 13 Recommendation to improve thermal insulation and add thermal mass Reflective layer e.g. low emissivity material such as aluminium or white paint Thermally reflective paints may not perform quite as well as manufacturers claim Lightweight cladding (to keep total thickness low) Moisture membrane (outside of insulation to reduce condensation potential) Bulk insulation R to the max! Thermal mass to buffer diurnal changes

14 Slide 14 Juluwarlu vault conditions (before) %RH temperature o C external conditions (available data) 40 Juluwarlu vault conditions (after) 35 o C %RH temperature o C external conditions (daily range) 14 Does it work? Thermal insulation added where possible, no opportunity for thermal mass or passive RH control (membrane) Data gathered from different sources, hard to overlay but the x & y scales are very similar and can be compared Roebourne climate similar November to January no significant seasonal difference While there is a diurnal change it is much lower ~4 o C

15 Slide %RH temperature o C external temp (daily range) external %RH (daily range) 15 To clarify thermal insulation has no real effect on relative humidity there may be slight effect depending on the type of insulation and the moisture barrier it presents e.g. loose fibre fill presents less of a barrier than expanded polystyrene foam.

16 Slide Case study, new building, temperate seasonal climate

17 Slide 17 Tropic of Capricorn Canberra 17

18 Slide 18 Tropic of Capricorn Canberra 18

19 Slide Design brief for a new vault DB = dry bulb WB = wet bulb

20 Slide New vaults (in blue) within existing building

21 Slide 21 powder coated steel expanded foam insulating layer (polyisocyanurate) Insulated panel 100mm = R 5.15 (US R 29.3) Adobe 100mm = R 0.20 (US R 1.13) 21 Solution, insulated panels (~R 10) with vapour proof gaskets

22 Slide vacant space moisture membrane under new vault walls sealing membrane

23 Slide 23 moisture membrane expanded polystyrene existing floor 23 Under floor insulation 200mm EPS (~R 5)

24 Slide 24 Indoor Air Quality (IAQ) green products tested for humans life expectancy performance the bottom line: research! choose the least harmful 24 One of the hardest problems was finding suitable building materials as coatings and sealants. Very hard to find anyone that makes specific products for building archives. Green products are tested for any impact on people in a domestic and office environment where there are multiple air changes and limited exposure time over 24 hours. Collections are exposed 24/7 and even low concentrations over a long period of time may have an adverse impact. Another issue with some products is that the green formulation may not as be as durable or robust as products containing substances incompatible with collections and may need to be replaced or redone more frequently. Choose based on available data. Look for products that claim low VOC and neutral cure.

25 Slide 25 energy consumption kwh winter summer Apr 15 May 15 Jun 15 Jul 15 Aug 15 Sep 15 Oct 15 Nov 15 Dec15 Jan 16 Feb 16 Mar 16 Apr 16 existing vault peak existing vault off-peak new vault peak new vault off-peak 25 Running costs of old vault versus the new vault Roughly half the energy (old vault also contained a majority of vaults at 16oC as well as 4oC) A large part of the reduction in cost is related to improved thermal insulation and the remainder are RH membrane and a better Building Management System.

26 Slide 26 microclimate controls moisture control %RH buffering fixed moisture content lowest steady state concentration positive/forced ventilation 26 Now let s consider some aspects of microclimates. %RH buffering with polyethylene or polypropylene bags + desiccants e.g. silica gel, molecular sieve, clays-montmorillonite, rice, tea Fixed moisture content e.g. FICA bags metallised polyester terephthalate, still requires temperature control to reduce the energy available for decomposition reactions Steady state concentration e.g. ventilated film cans - maximises diffusion BUT incompatible with microclimate moisture control Slide 27

27 Camellia sinensis 27 Case study: low cost material Tea: the world s most popular beverage after water. Dried tea leaves have been used for centuries in Japan as a deodouriser and desiccant, where it is known as chagra

28 Sorbency (acetic acid) Bell 2016 Desiccant Willet, Newnham, Nell 2015 Slide ? Molecular Activated Silica Gel Sieve charcoal Red tea Green tea Black tea Black tea Dried Brewed black tea black tea Mol Sieve 4A Silica Gel A. charcoal 28 Two studies into tea from University of Melbourne Master s Degree conservation students Top: tea as a desiccant I have serious doubts about the molecular sieve result, I don t feel the activation was adequately performed. However tea is a comparable desiccant to silica gel. Bottom: tea as a sorbent compared with known high efficiency sorbents. In this study molecular sieve performed as expected.

29 Slide 29 These results suggest tea may not be as effective at adsorbing off-gassed acetic acid as the industry recommended commercial adsorbent, molecular sieves. However, other considerations support further research into the application of tea as an alternative adsorbent. the use of brewed tea offers the additional sustainability benefits of repurposing a waste product, reducing material usage and eliminating material costs. Finally, the use of tea would increase accessibility for small, remote, underfunded or community run archives to preservation materials for their CA collections. Julianne E. Bell : Extracts from Julianne s thesis conclusion. There are other lower cost alternatives to explore, for example bamboo charcoal, which has been used for centuries in China and Japan as a deodoriser and desiccant. Or may just dried bamboo? There is a still a lot of research to be done in this area.