Why go Green?

Why go Green?

Maybe I just throw out the question. You can reflect about the reason to go green.

Please give your thoughts in the comments.

And I also found a website that has many tips on going Green:

http://www.greenlivingtips.com/

But it appears it is focused on "how". I can't find much about "why". (So I supposed it is for the "converted", not for the skeptics.)

Do you believe we can afford not to go Green?

Is this really a “Sustainable Development” or is it only a “Greenwash”?

Another post I wrote back in 2007. Still valid!!!

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Well, “Sustainable Development” …..

Seems like everyone has their own idea of SD!

But when it comes to developing & constructing a building, I believe we should objectively use some rating tools to determine how “green” a building is.

And in the construction industry, seems like not everyone has a “proper” understand of sustainable development!

I refer to a project that I am involved in recently. (2007)

The client wants to build a “Green” building. I am the mechanical and ESD consultant of the project.

There are a few ESD initiatives proposed for the building, such as heat recovery, ABGR 4.5 stars, 4 Green Star, solar hot water system, etc.

However, I see some other things not going the right direction.

It was supposed to be “Energy Efficient”.

Enormous glazing area is not “energy-friendly”! This is because when comparing the heat conduction rates through glass and through normal wall are quite different.

If we use the U-value required by BCA Part J1.5, which has R-value of 1.8 or U-value of 0.56 compare to normal single clear glazing of 5.84, there is a factor of around 10, i.e. glass gains 10 times the heat through conduction compare to a BCA compliant wall!!!!! They want as much (cheap single clear) glass as possible, full width & full height!! Is this “Green”?

But then, they want to boast the building being very “sustainable” and “green”, first in this and first in that …..!!!

I don’t see it that way. I only see its performance as “approaching” the minimum standard. (Not exactly true green.)

And if you have a look at the respective authorities’ website, we can’t make a claim and reference to a rating scheme if we are not achieving to the required standard.

“We want you to make the report more COLORFUL!!”…..

Sorry, UNABLE TO COMPLY!!

對付氣候變化是否符合經濟原則？

A letter to Ming Pao on the economies of Climate Change.

Worth reading.

趙耀華﹕對付氣候變化是否符合經濟原則？

【明 報專訊】可以這樣說，遍數眼下熱門國際議題，除了金融危機之外，沒有別的事情比氣候變化更引人注目了。似乎一般人也同意氣候變化是個非常嚴峻的問題，解決 它已經到了刻不容緩的地步。但是，值得注意的是，這種態度和氣候變化經濟學的主流結論相當不同。耶魯大學的經濟學者諾德豪斯（William Nordhaus）在2007就說過，根據氣候變化經濟學的研究成果，「最優的減緩氣候變化的經濟政策是：在短期適度地減少排放量，在中長期大量減少排放 量……這個結論經過了多種不同的建模策略測試，考慮了各種氣候目標、科學參數，還經歷了10年的整合評估模型修正」。

最近的經濟危機已經損害了主流經濟學界的名聲。他們不但未能在危機爆發前發出警報，更嚴重的是長期對金融市場放鬆管制的潛在危險視而不見。我擔心假若我們果真追隨諾德豪斯的漸進策略，終有一天我們會後悔對氣候變化做得不夠，就像我們現在後悔對金融管制得不夠一樣。

幸運的是，諾德豪斯的意見並非是唯一的意見。由英國政府委託、曾任世界銀行首席經濟學家的斯特恩（Nicholas Stern）所主持的2006《斯特恩報告》，就提出了相反的意見，這個報告主張雷厲風行，迅速大量減排二氧化碳。當時的首相貝理雅在報告面世時就說： 「毫無疑問，如果科學是正確的話，我們星球的未來是災難性的。在未來10到15年間，如果缺乏國際間的激進的二氧化碳減排措施，強有力的證據證明我們將錯 失控制氣溫上升的時機。」

折現率之爭

氣候經濟學家使用一種叫「成本效益分析」的分析工具。在有關個人的成本效益分析上，我們常常需要把目下的支出收入與將來的支出收入比較。舉例說，如 果你把手頭上的1萬元放進銀行收取利息（舉例說每年2厘），那麼10年後就可以取回本金加利息一共10,000×1.0210 =12,190元。照此推算，10年後的1萬元經過貼現，其實只等於眼下的8,197元（貼現率為每年2厘）。

氣候經濟學中的成本效益分析，借用了這種在個人決策中使用的貼現方法，使得將來的人的利害得失可以與我們這一代人的利害得失比較。斯特恩使用的經濟 模型和以諾德豪斯為代表的主流氣候經濟學界所使用的其實大同小異，主要分別在於他們用上了不同的貼現率，即對未來的人的福祉給予不同程度的重視。斯特恩給 予100年後那一代人的福祉的重視程度，相當於對當今我們這代人重視程度的0.90倍，而諾德豪斯給予的則只是0.22倍！

在研究個人的決策問題時使用折現毫無爭議，但把它用在研究社會上的代際問題卻缺乏根據。在前一類問題中，當初的決策人也是日後的承受者；在後一類問 題中，未來的人沒有在今天作出決定的權利，卻要承受這些決定的後果。認為未來的人相對我們這代人而言不那麼重要，這種處理方法並不符合任何道德的基礎，諾 德豪斯那樣高的貼現率，簡直是對人權的踐踏！

事實上，即使以追求沒有貼現的各代福祉之和的極大化也有問題。因為這意味覑：假如一個政策為當今這代人增加兩個單位的福祉，而對未來的一代減少一個單位的福祉，那麼這種政策算得上是個進步。但是，我們真的這樣認為嗎？

代際公平的問題

另一個耶魯經濟學家、政治學家羅默（John Roemer）提出了一個代際公平的原則：一個中立無私的決策人做出的決策，應該以提高各代人中福祉最低那代人的福祉為目標。（把這個縱向的代際原則，改 變成為橫向的原則便很清楚：香港整體的福祉，不是以最富有的人的收入來判斷，而是以最窮的人有沒有過體面的生活來判斷的！）。當我們這代人作出的決策符合 這個原則，未來的人一定不會比我們活得差，因此這種原則也可以稱為可持續性原則（sustainability），或者最小最大原則（minimax）。 讀者也許會問：如果我們將未來的人的福祉看得那麼重要，我們這一代豈不是要受苦？

別擔心，羅默和他的合著者給我們帶來了好消息。他們在一篇論文中發現，即使按照聯合國氣 候變化小組（IPCC）給定的方案減排二氧化碳的話，包括我們在內的今後每代人的生活水準，都可以維持於高於2000年的生活水準30%之上，而不需要下 降。他們還證明了，即使我們還要求以後的人生活得比我們好，只要增長速度不是太大時，我們當今一代人同樣不需要受苦。值得注意的是，在這項研究中使用的 「生活水準」概念，並不僅僅指消費，還包括知識水準﹑對大自然的保育程度等等。

大災難的後果

哈佛大學經濟學家魏茨曼（Martin Weitzman）則批評，主流的氣候變化經濟中在使用成本效益分析方法時，往往忽略了大災難出現的可能性。在經濟學中，一個變數的不確定性是通過一個概 率分佈函數來表示的。但在標準的成本效益分析中，變數取得極端（極大或者極小）的數值的可能性是忽略不作處理的，即把概率分佈函數的兩條尾巴去掉。魏茨曼 認為，在一般問題上，這種處理方法無可厚非，但是在氣候變化問題上，這樣作出來的分析是非常不可靠的。這樣做等於把我們想要研究的﹑並設法提防的大災難， 事先就排除在分析之外！

魏茨曼認為主流的氣候變化經濟家應該老老實實地把這些不足告訴決策者，由於氣候變化的問題實在太複雜了，成本效益分析並不那麼可靠，「這確實使我們 不太高興，但事實畢竟是事實，我們總不能為了令自己的研究看起來更為客觀科學一點，就可以迴避甚至否定這個事實」！（魏茨曼並不是個小輩，在今年諾貝爾獎公布得獎名單之前，他便和諾德豪斯一起被視為可能人選。）

筆者認同斯特恩﹑羅默﹑魏茨曼等人的看法。斯特恩提醒我們要有長遠的眼光；羅默告訴我們代際公平的原則，而衡量人類生活品質時，還應該包括消費品以外的東西；魏茨曼則警告我們不要夜郎自大，要知道現有知識的局限。

作者是香港大學經濟金融學院副教授

I guess the.Darwinian may have some say about this, esp. on inter-generation asset.

Thermal Comfort Science

This is a post I made in 2007 on thermal comfort science basing on PMV calculations. I actually believe thermal comfort sensation in normal people has changed.

Somehow, an environemnt used to be bearable is now unbearable when people "experience" another environment and want to enjoy an "comfortable" environment at OPM.

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Thermal Comfort Science 熱環境舒適性

Recently, I completed a report related to thermal comfort.

So I think it is beneficial to raise the awareness and boarden the general public about thermal comfort.

Air temperature is related to thermal comfort but it is not the only factor.

ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) has devised a thermal sensation scale as below:

+3 Hot
+2 Warm
+1 Slightly warm
0 Neutral
-1 Slightly cool
-2 Cool
-3 Cold

Extensive research was done in Kansas University by Ole Fanger. His team has found out that there are gerneally six factors that will affect the sensation of thermal comfort in human.

The six factors are:
1. Air temperature
2. Mean radiant tempersture (this is related to the surface temperature of the surrounding environment. It can't be measured but can be calculated by some mathematical formulae)
3. Humidity
4. Air speed
5. Clothing
6. Human activity

A computer software to estimate the PMV can be downloaded from this link:

http://www.freedownloadscenter.c ... fort_Estimator.html

The ASHRAE standard recommends that a PMV range of -0.5 to +0.5 is good for an indoor office environment.

For the project that I work on, currently a PMV range of -1.0 to +1.0 is thought acceptable.

Basing on this, I found that even an air temperature of 30 degree is still acceptable if other factors can compensate for that:

0.3 clo which is equivalent to T-shirt and shorts
1.3 met which is standing or shopping leisurely
1.3 m/s air speed, this is somehow breezy but acceptable in that environment
60% relative humidity
31 deg C mean radiant temperature, that building does not have any large window and radiation is very little.

So if you experience a hot environment, try the following method rather than just turning on the air conditioner:
1. Lower the curtain
2. Take off your clothes, just leave T-shirt and shorts on
3. Turn on you fan(s)
4. Switch off large appliances
5. Keep yourself calm and don't move about
6. You may spray some water over yourself, probably over the arms and legs to cool yourself down by evaporation.

The birth of blog from Ray Chung on Sustainability and Others

Hello, world!

Classic opening for computer programming books.

In some conversations with friends, families and others, it appears sustainability is not that familiar or critical to many of them.

So I think I start this blog to desribe part of my work as a sustainability / ESD (environmentally sustainable development) worker (Green collar worker).

Is energy efficiency only about saving money?

Why I annoy people to switch off the lights, turn off the A/C, leave the blinds down, etc .....?

I'll talk about the PHILOSOPHY behind (I'd try it in plain English but there's no guarantee.)

I already have some work ready from previous effort.

Stay Tuned.