行政院國家科學委員會專題研究計畫成果報告

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行政院國家科學委員會專題研究計畫成果報告

綠色建築三合一整合光伏電熱太陽能板(PV/T)空氣收集器, 地熱空氣交換器(EAHE)及鋪設穩態形狀相變材料地板

(SSPCM)的能量與最大可用能之分析研究研究成果報告(精簡版)

計畫類別：個別型

計畫編號： NSC 99-2221-E-216-030-

執行期間： 99 年 08 月 01 日至 100 年 07 月 31 日執行單位：中華大學機械工程學系

計畫主持人：蔡博章

計畫參與人員：碩士班研究生-兼任助理人員：張宇志碩士班研究生-兼任助理人員：賴世傑

報告附件：出席國際會議研究心得報告及發表論文

公開資訊：本計畫涉及專利或其他智慧財產權，2 年後可公開查詢

中華民國 100 年 10 月 31 日

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中文摘要：建築物越來越注重本身自己就是節能減碳有效率，因此自然通風、太陽能加溫與致冷、地溫空氣熱交換、自然光線及避陽遮蔭…等自然被動式不需要消耗太多能量的設置，將是綠色建築的不二選擇，本研究三機一體將薄膜光伏電熱太陽能板空氣收集器(PV/T aircollector), 收集熱氣驅動氣流、搭配地溫空氣熱交換(EAHE)來的氣流與吸收透過窗戶或太陽能板光線的穩態形狀相變材料地板(SSPCM)之儲熱儲能，利用新設計分階相變活塞氣缸壓氣機作系統氣流、溫度的自然調配，整合出一棟完全被動式混成系統建築。考慮新材料與建築服務結合的綠色設計新觀念，再以一棟位於台灣新竹地區沒有空調的建物為探討對象，來數值分析仲夏夜晚通風情況下，氣、電及熱的需求與影響，分析時程含蓋日、月及年，先針對薄膜光伏電熱太陽能板與各次系統之物理數學模型(Model)驗證，再發展出被動式混成系統建築的完整物理數學模型，搭配 MATHLAB、CFD 軟體協助而得到分析解及數值解。致於現在正在進行利用熵值公式 (enthalpy formulation)及 Voller 與 Patankar 之控制容積數值技術求解二維暫態能量守恆搭配 Stefan 移動邊界問題之福傳程式組 Hybrid-HVAC，也將配合本棟被動式混成系統建築的個別次系統做程式修改為 Hybrid-HVACP，此程式可以幫忙材料作驗證，以及協助太陽能電池空氣收集器、地溫空氣熱交換及穩態形狀相變材料地板等系統作設計，為綠色建築-節能省能屋的最佳化設計與能量分析，提供有利的工具。

本研究將花費一年時間發展，以 2010 年 8 月 1 日到 31 日 0am- 24pm 及 2011 年各個月新竹市的氣象資料當樣本，設定系統與次系統參數到本樣品屋，進行可行性評估、加溫與致冷能力分析、空調性能、次系統操作條件改變時如空氣流量改變，環境溫度與室內溫度的變化及隨氣候分級環境溫度變化時，本被動式混成系統建築的逐月逐年的能量分析…等，希望本研究成果能協助居民對各式各樣節能省能技術作選擇，並促成人們有健康、舒適地居住環境的美夢能成真。

英文摘要： The self-sufficiency of buildings is becoming increasingly

important. Therefore, devices for natural ventilation, solar heating and cooling, ground cooling (earth- air heat exchangers), natural lighting, shading from the sun, and other devices that use a passive mode strategy have been developed. Sustainability-oriented choices that might in the pass have been considered to be optional are now necessary. In this work, thin film photovoltaic technology is utilized in buildings. An integrated photovoltaic /thermal (PV/T) air

collector to collect hot air and drive air flow, and mixing the air flow from earth-air heat exchanger (EAHE) and hot air flow to the floor that is made of shape-stabilized phase change material (SSPCM) floor inside greenhouse, a SSPCM absorbs energy form

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solar light that enters through windows and solar panels. A piston cylinder air compressor adjusts the moderate control of air flow and the ambient temperature and temperature of room in the hybrid system. The hybrid system using natural ventilation in passive strategies designs an innovative HVAC system can be called ’lung’

of a building. The design process integrated with ‘‘whole building approach’ and ‘‘new material’ is used to analyze the theoretical performance of this building by energetic analyses for the weather in HsinChu. A mathematic model will be resolved by the helps of MATLAB 7.0 program and CFD software. The energy required by air-conditioning and thermal will be predicted. A finite difference- Fortran program (Hybrid-HVAC) is developed based upon the 2D unsteady heat equation with a Stefan moving boundary problem.

This program is modified into a Hybrid-HVACP and should enable the hybrid system building with the PV/T、EAHE and SSPCM to be solved numerically with high accuracy. The simulation results in this work reveal that if the difference between ground temperature and ambient temperature is less than 5 K, such as in HsinChu city, the HVAC results obtained using EAHE are unsatisfactory, and so EAHE yields better results in areas with large temperature

differences.

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行政院國家科學委員會補助專題研究計畫 ■ 成果報告

□期中進度報告

綠色建築三合一整合光伏電熱太陽能板(PV/T)空氣收集器,地熱空氣交換器 (EAHE)及鋪設穩態形狀相變材料地板(SSPCM)的能量與最大可用能之分析 研究

計畫類別： ■ 個別型計畫 □整合型計畫計畫編號：NSC－99－2221－ E －216－030

執行期間： 99 年 08 月 01 日至 100 年 07 月 31 日

執行機構及系所：

中華大學機械工程學系

計畫主持人：蔡博章共同主持人：

計畫參與人員：張宇志、賴世傑

成果報告類型(依經費核定清單規定繳交)：■精簡報告 □完整報告

本計畫除繳交成果報告外，另須繳交以下出國心得報告：

□赴國外出差或研習心得報告

□赴大陸地區出差或研習心得報告

■出席國際學術會議心得報告

□國際合作研究計畫國外研究報告

處理方式：除列管計畫及下列情形者外，得立即公開查詢

□涉及專利或其他智慧財產權，□一年■二年後可公開查詢中華民國 100 年 10 月 26 日

附件一

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目錄:

附件一: 行政院國家科學委員會補助專題研究計畫成果報告 一、目錄

二、報告內容 三、參考文獻 四、計畫成果自評

附件二: 國科會補助專題研究計畫成果報告自評表 附件三: 國科會補助計畫衍生研發成果推廣資料表

附件四: 國科會補助專題研究計畫項下出席國際學術會議心得報告

附件五: 國科會補助專題研究計畫項下赴國外(或大陸地區)出差或研習心得 報告(無)

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Theoretical performance of integrated photovoltaic /thermal air collector, earth-air heat exchanger and greenhouse with a floor of shape-stabilized phase-change material: evaluation

by energetic analyses

蔡博章¹、張宇志²、賴世傑³

1中華大學機械工程研究所教授

2,3中華大學機械工程研究所研究生

國科會計畫編號. : NSC 99-2221-E-216-030

Abstract

The self-sufficiency of buildings is becoming increasingly important. Therefore, devices for natural ventilation, solar heating and cooling, ground cooling (earth- air heat exchangers), natural lighting, shading from the sun, and other devices that use a passive mode strategy have been developed. Sustainability-oriented choices that might in the pass have been considered to be optional are now necessary. In this work, thin film photovoltaic technology is utilized in buildings. An integrated photovoltaic /thermal (PV/T) air collector to collect hot air and drive air flow, and mixing the air flow from earth-air heat exchanger (EAHE) and hot air flow to the floor that is made of shape-stabilized phase change material (SSPCM) floor inside greenhouse, a SSPCM absorbs energy form solar light that enters through windows and solar panels. A piston cylinder air compressor adjusts the moderate control of air flow and the ambient temperature and temperature of room in the hybrid system. The hybrid system using natural ventilation in passive strategies designs an innovative HVAC system can be called “lung” of a building. The design process integrated with ‘‘whole building approach” and ‘‘new material” is used to analyze the theoretical performance of this building by energetic analyses for the weather in HsinChu. A mathematic model will be resolved by the helps of MATLAB 7.0 program and CFD software. The energy required by air-conditioning and thermal will be predicted. A finite difference-Fortran program (Hybrid-HVAC) is developed based upon the 2D unsteady heat equation with a Stefan moving boundary problem. This program is modified into a Hybrid-HVACP and should enable the hybrid system building with the PV/T、EAHE and SSPCM to be solved numerically with high accuracy.

The simulation results in this work reveal that if the difference between ground temperature and ambient temperature is less than 5 K, such as in HsinChu city, the HVAC results obtained using EAHE are unsatisfactory, and so EAHE yields better results in areas with large temperature differences.

Keywords: Photovoltaic/thermal air collector, Earth air heat exchanger, Shape-stabilized phase change material, HVAC, Solar energy.

I. Introduction

In Europe, almost half (about 40%) of all power consumed is associated with buildings, especially in their construction and maintenance, but mostly in their operation. Therefore, an increasing attention is being paid to the self-sufficiency of buildings, as demonstrated by the new European (and national) regulations concerning the energetic certification of buildings. Sustainability-oriented choices that could have been considered optional previously are now necessary. Therefore, energy is no longer something of interest only to researchers, but is now a ‘‘new consideration” in the design processes of architects and engineers.

This investigation concerns the weather in HsinChu city [1], and the application of thin film photovoltaic technology in buildings. An integrated photovoltaic/thermal (PV/T) air collector for collecting hot air and driving air flow mixes the air flow from the earth-air heat exchanger (EAHE). Hot air flows to the floor that is made of shape-stabilized phase change material (SSPCM) floor inside greenhouse. SSPCM absorbs energy form solar light that enters through windows and solar panels. A piston cylinder air compressor adjusts moderate air flow and ambient and room temperatures in the hybrid system. The hybrid system using natural ventilation in passive strategies designs an innovative HVAC system can be called

“lung” of a building.

The literature on the PV/T integrated hybrid system is surveyed. Chow [2] analyzed the performance of a photovoltaic-thermal collector by using an explicit dynamic model and found a thermal efficiency of 60%.

Arrangements for utilizing thermal energy as well as electrical energy that include a photovoltaic module are referred to as the hybrid PV/T systems. The thermal energy that is obtained from the hybrid photovoltaic (PV/T) system is supplied to the greenhouse for heating.

Tiwari and Sodha [3] examined the thermal performance of a hybrid with photovoltaic/thermal (PV/T) air collector. Nayak and Tiwari [4] studied the performance evaluation of a hybrid photovoltaic/thermal (PV/T) integrated greenhouse system. They obtained a thermal efficiency of the hybrid

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photovoltaic/thermal (PV/T) air collector around 34%

and a thermal efficiency of the photovoltaic/thermal (PV/T) without airflow is of 8.5%. The thermal efficiency of the PV/T air collector was increased by 25.5% by causing the air to flow. Barnwal and Tiwari [5]

investigated the design, construction and testing of a hybrid photovoltaic integrated greenhouse dryer. Dincer [6] studied the energetic performance of heating systems for building in two geothermal districts and found energy efficiencies of heating systems in the Balcova geothermal district and Salihli geothermal district of 39.36% and 59.31%, respectively. Dincer [7] examined the relationships between energy and exergy, energy and sustainable development, energy policy-making, exergy and the environment and exergy. In study of the hybrid system design, and the construction and testing of integrated hybrid photovoltaics, the work of Nayak and Tiwari [8] [9], Dincer [7] is drawn upon to conduct the theoretical analysis and that of Tsai [10] is used to design heat exchanger. The installation of a wall and floor made of the shape-stabilized phase change material (SSPCM) inside building has already studied by the present authors [11-12].

II. PHYSICAL AND MATHEMATICAL ANALYSIS AND MODELING

A rectangular U-shaped EAHE whose bottom is 40m long, 10cm wide and 10cm high and 5m deep, and whose sides are 5m high, 10cm wide and 10cm high on both sides, the thickness of all channel duct surfaces is 10mm. (Fig. 1). The model room (with no roof) is 3.9m long、3.3m wide and 2.7m high. The cement layer is 300mm thick, the layer SSPCM is 100mm thick, the cross sectional area of the air outlet is 100mm x 100mm, and the temperature below 5m below the surface of the ground surface is maintained at 298 K.

1. Energy balance equations for photovoltaic and earth-air heat exchanger integrated greenhouse The energy balance equations for different components of a greenhouse that is combined with a photovoltaic (PV/T) system and an earth-air heat exchanger (EAHE) are as follows: (Fig. 2)

The term qU denotes the useful thermal energy that is obtained from a photovoltaic (PV/T) system and Qu is the useful thermal energy that is obtained from an earth-air heat exchanger (EAHE).

（i）The amount of useful thermal energy obtained hourly form the PV/T system

( ) { ( ) ( ) ( )}

[

⁽ ⁾

]

( ) ( ) ( )

{p p eff L r a}

R

c m bU a r L eff p p L

a a r airout a a U

T T U t I h h F

e T T U t I h U h

c T m T c m

q ^L ^a^a

−

=

−

=

−

= ⁻

ατ

2 1

2

1 1 ^&

&

(1)

where

( )

[

^bU^L^m^a^c^a

]

L a a

R e

U c

F =m& 1− − ^&

（ii）The amount of useful thermal energy obtained hourly form the EAHE

(

_r

)

a a R

u F m c T T

Q& = ′ ₀−

（2）

where ^F^R^′ ⁼¹⁻ê⁻⁽²^π^r¹^h^g^m^&â^câ⁾^L^′

Combining equations of (i) and (ii) yields the first order partial differential equation:

( )

dTr aTr B t dt

+ = ， ( ) ^{F t}( ) ( )^UA effTa B t

M Ca a +

= ，

a1 a

M Ca a

= (3)

The analytical solution of Eq. (3) can be written as

( ) (

¹

)

B t at at

Tr e T ero

a

− −

= − + ( 4 ) where Tro is the greenhouse air temperature at t = 0 and B(t)is the average of B(t) for the time interval 0 and t, and a is constant during the time. The rate of daily useful thermal energy obtained from PV/T system:

( )

^q^& ^daily ⁼^F^R

{

^h^pi^h^p²

( ) ( )

^ατ ^eff ^{I t} ⁻^U^L^∑

(

^T^r⁻^T^a

) }

^{( 5 )}

2 1 1

r hgfm Ca a L

FR e

π

⎛ ⎞

⎜ ⎟

⎝ ⎠

− ′

′ = − &

The rate of daily useful thermal energy obtained from EAHE:

( )Q&u daily =FR′m Ca a

[

T0−Tr

]

(6) And final the total useful thermal energy obtained

( )^Q_u _tot ( )^q_u _daily ( )^Q_u _daily

daily = +

⎡ ⎤

⎣ ^& ⎦ ^& ^& (7)

III. NUMERICAL TECHNIQUE

1. Model room (with or without a roof)

The model room (with no roof) that is used in the analysis is a concrete chamber with dimensions of 3.9 m (length) x 3.3 m (width) x 2.7 m (height). The dimensions of earth-air heat exchanger (EAHE) are given above. (Fig. 3)

2. Input parameters of the model room and applying software

In this study, Gambit was used to construct a solid model and grid mesh, and then Fluent was used to solve the flow and thermal field. Table 1 presents all parameters of the building and material properties of SSPCM. Table 2 presents the conditions of environments outside the model room.

3. Establish grid cells

Fig. 4 presents cells in the grid mesh for this model room (with no roof).

Ground (4662.791 m³) ：249,885 cells Concrete layer (113.359 m³) ： 193,403 cells SSPCM layer (3.441 m³) ：136,400 cells Floor-wood (0.891 m³) ：7128 cells EAHE (0.418m³) ：3352 cells Air outlet (0.004 m³) ：32cells

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4. Settings of the Fluent

The settings used in the Fluent software are as follows:

1. Solver ：Segregated 2. Space：3D

3. Velocity formulation ：Absolute 4. Gradient option ：Cell-Based 5. Formulation ：Implicit 6. Time ：Unsteady

7. Unsteady formulation ：1^st-Order Implicit 8. Porous formulation ：Superficial Velocity 9. Laminar

5. Initial conditions

Energy stored in the cycle is absorbed heat

The ambient temperature and pressure are 303 K and 1atm respectively. The temperature of SSPCM layer is assumed to be at a constant temperature 293 K, the optimal time (i.e. melting/fusing temperature) and its latent capacity is 265MJ/m³. The initial condition (t=0) of indoor air temperature is 303 K. On the contrary, Energy released in the cycle is lost heat

The ambient temperature and pressure is 289 K and 1atm respectively. The temperature of SSPCM layer is assumed to be at a constant temperature 303 K, the optimal time (i.e. melting/fusing temperature, and its latent capacity is 265MJ/m³. The initial condition (t=0) of indoor air temperature is 289 K.

Each time increment △t is 0.1 sec. Iterations are performed up to the specific time until the convergence criteria are satisfied.

The temperature 5m below the ground surface is kept constant at 298K.

6. Boundary conditions

The embedding macro files in the Fluent are used to set the boundary conditions and our case is unsteady. The maximum of solar radiation on the south wall is 900Wm^-2 and in the HsinChu city, the wind in the summer is southern at 6 ms^-1 and the average outdoor temperature is 302.96 K, in winter, the wind is southern 6.6 ms^-1 and the average outdoor temperature is 288.9 K.

(Table 2)

7. Convergence criteria

To determine any number of flow field changes in the iterative process, the simulation convergence criteria in Table 3 are imposed.

8. Computational procedure of energy analysis Equations of the energy balance derived for greenhouse coupled with photovoltaic system and earth air heat exchanger (EAHE), have been solved with the help of a computer program, based on Matlab 7.1 software.

IV. Result and Discussion

A. Simulated temperature results of passive SSPCM

Energy stored in the cycle is absorbed heat

The ambient temperature and pressure are 303 K and 1atm respectively. The temperature of SSPCM layer is assumed to be at a constant temperature 293 K, the optimal temperature (i.e. melting/fusing temperature, and its latent capacity is 265MJ/m³. The initial condition (t=0) of indoor air temperature is assumed to be 303 K. At this time, initially t = 0, the indoor air temperature exceeds the temperature of the SSPCM layer. Then all SSPCM layers start to absorb heat.

Numerical results reveal that as time passes, the average indoor temperature decreases. The average indoor temperature drops from 303 K to 295.93 K within 60 minutes.

SSPCM + EAHE (indoor room temperature around 302.74 K)

In Table 4, the air temperature of EAHE rapidly reaches thermal equilibrium with the ground temperature, and temperature of air that moves from EAHE to the indoor space of the model room remained at around 302.74 K. Little change in air temperature occurs after the heat is exchanged through EAHE. Because the difference between the ambient temperature and the EAHE temperature is small. Figures.5 a-d plot simulated indoor air temperature vs. time (YZ plane at middle X) for the SSPCM + EAHE in an energy stored cycle.

Indoor air temperature does not fall but rises at t = 20 minute because SSPCM loses heat more slowly than does the air-out from EAHE, but later at t = 30 minute the indoor air temperature is in thermal equilibrium at 300.52 K.

On the contrary,

Energy released in the cycle is removed heat

The ambient temperature and pressure are 289 K, and 1atm respectively. The temperature of the SSPCM layer is assumed to be at a constant temperature 303 K, the optimal time (i.e. melting/fusing temperature), and its latent capacity is 265MJ/m³. The initial condition (t=0) of indoor air temperature is assumed to be 289 K. At this time, initially t = 0, the indoor air temperature is smaller than the temperature of the SSPCM layer, subsequently, all SSPCM layers start to release heat.

Numerical results reveal that as time passes, the average indoor temperature increases. The average indoor temperature increases from 289 K to 298.8 K within 60 minutes. This process produces heating effect at night time or in the winter.

SSPCM + EAHE (indoor room temperature around 291.35 K)

In Table 5, the air temperature of EAHE rapidly reaches thermal equilibrium with the ground temperature, and the temperature of air from EAHE to the indoor space of the model room remains at around 291.35 K. The air temperature changes only slightly

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upon after the heat exchange through EAHE, because the ambient temperature and EAHE temperature differ only slightly. Figures 6 a-d plot simulated indoor air temperature vs. time (YZ plane at middle X) for the SSPCM+ EAHE in an energy released cycle. Indoor air temperature does not rise but falls at t = 20 minute because heat is absorbed by SSPCM more slowly than the air-out from EAHE, but later at t = 30 minute the indoor air temperature reaches thermal equilibrium at 294.42 K.

B. Comparison between numerical and analytical results for hourly variation of outdoor air temperature The above discussions of SSPCM concern idealized cases since the temperature of SSPCM was forced to be constant, therefore latent heat capacity causes melting or fusing in a short period of time, and the temperature difference between the average indoor temperature and indoor air temperature is large around 8 K to 9 K. In fact the average indoor temperature varies sinusoidal cycle with relation to optimal SSPCM temperature. The temperature differences between the average indoor temperature and indoor air temperature in both energy stored cycle and energy released cycle are around 2 K to 4 K. The analytical results have been reported by Xiao [13]. Therefore we can compare our numerical results with each other based upon the hourly variation of outdoor air temperature in HsinChu city on one day in July. (the indoor air temperature is simplified equal to outdoor air temperature). From Fig. 7 indicates that numerical and analytical results are mutually consistent.

C. Results of energy analysis

Eq. (4) has been used for calculating greenhouse air temperature under weather conditions for HsinChu city for the following case:

Photovoltaic is operated and earth air heat exchanger is operated for 24 hr for a typical summer or winter day.

Hourly variation of room air temperature when operated with earth air heat exchanger for 24 hr (with the operation of photovoltaic/thermal system) for a typical summer day is shown in Fig 8. In this case it is seen that room air temperature is around 4–5 K lower than the ambient air temperature at 4 pm, while it is 2–3 K lower at 4 am, due to continuous flow of cold air from earth air heat exchanger to the room.

Hourly variation of room air temperature when operated with earth air heat exchanger for 24 hr (with the operation of photovoltaic/thermal system) for a typical winter day is shown in Fig 9. In this case it is seen that room air temperature is around 3–4 K higher than the ambient air temperature at 1 pm, while it is 5–6 K higher at 5 am, due to continuous flow of hot air from earth air heat exchanger to the room.

Fig. 10 shows the variation of hourly useful thermal energy (MJ) when operated with photovoltaic (PV/T) system and with earth air heat exchanger (EAHE) for a typical summer day. It has been observed that at 12 pm,

useful thermal energy is calculated as 16 MJ with the operation of photovoltaic/thermal (PV/T) system, while between 5 and 6 pm, the useful thermal energy decreases due to fall of temperature during evening.

And useful thermal energy continuously fall down to 4 MJ while between 3 and 4 am.

Fig. 11 shows the variation of hourly useful thermal energy (MJ) when operated with photovoltaic (PV/T) system and with earth air heat exchanger (EAHE) for a typical winter day. It has been observed that at 12 pm, useful thermal energy is calculated as 16 MJ with the operation of photovoltaic/thermal (PV/T) system, while between 4 and 5 pm, the useful thermal energy decreases due to fall of temperature during evening. It then increases to 14.5 MJ with the operation earth air heat exchanger during night.

V. Conclusions

This study established a close to the actual physical situation in a hybrid system as a whole including sub-systems in this new analysis. The following conclusions are drawn:

(1) The hybrid system’s BIPV、TE、SSPCM heat sink and EAHE efficiency gains can ensure energy-efficiency and cleanness. They can also reduce the CO2 emissions.

(2) The hybrid system has the low total input power and its use constitutes an active approach to energy-saving.

(3) SSPCM consists of paraffin as dispersed PCM and high-density polyethylene (HDPE) or another material as a supporting material. The total stored energy is comparable with that of traditional PCMs.

(4) SSPCMs of the ceiling and floor can use the same material, temperature range of 297 K to 300 K start energy stored cycle and temperature range of 289 K to 293 K start energy released cycle.

(5) Reducing the temperature difference between the ceiling and the floor to less than 4 K increases the comfortableness of humans.

(6) 297 K is the most comfortable temperature in the HsinChu area.

(7) The simulation results reveal that if the difference between the ground temperature and the ambient temperature is less than 5 K, such as in HsinChu city obtained results are unsatisfactory, so the use of EAHE in areas with a large temperature difference yields better results.

(8) The effect of EAHE is not superimposed on additive with the effect of SSPCM, many parameters need to be considered such as materials, size and operating characteristics, therefore the design optimization is needed.

(9)Working fluid air of EAHE may be replaced with water or refrigerant which has a much larger temperature range than air.

(10) Hourly useful thermal energy (MJ) when operated with photovoltaic (PV/T) system and with earth air heat exchanger (EAHE) for a typical summer day. It has

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been observed that at 12 pm, useful thermal energy is calculated as 16 MJ with the operation of photovoltaic/thermal (PV/T) system, then the useful thermal energy decreases due to fall of temperature during evening. And useful thermal energy continuously fall down to 4 MJ while between 3 and 4 am.

(11) hourly useful thermal energy (MJ) when operated with photovoltaic (PV/T) system and with earth air heat exchanger (EAHE) for a typical winter day. It has been observed that at 12 pm, useful thermal energy is calculated as 16 MJ with the operation of photovoltaic/thermal (PV/T) system, while between 4 and 5 pm, the useful thermal energy decreases due to fall of temperature during evening. It then increases to 14.5 MJ with the operation earth air heat exchanger during night.

VI. Acknowledgement

We hereby express our thanks to the National Science Council for the support of research project NSC99-2221-E-216-030.

VII. References

[1] Central Weather Bureau , Taipei, Taiwan:

http://www.cwb.gov.tw/ (2011)

[2] T.T. Chow, Performance analysis of photovoltaic-thermal collector by explicit dynamic model, Solar Energy 75 (2), 143 (2003)

[3] A. Tiwari , M.S. Sodha , Performance evaluation of solar PV/T system: an experimental validation, Solar Energy 80 (7), 751 (2006)

[4] S. Nayak, A. Tiwari, Performance evaluation for an integrated photovoltaic/thermal greenhouse system, International Journal for Agricultural Research 2(3), 211 (2007)

[5] P. Barnwal, A. Tiwari, Design, construction and testing of hybrid photovoltaic integrated greenhouse dryer, International Journal of Agricultural Research (IJAR)3 (2), 110 (2008)

[6] I. Dincer, A. Hepbasli, L. Ozgener, Performance investigation of two geothermal district heating systems for building applications, Energy Analysis, Energy and Buildings 38, 286 (2006)

[7] I. Dincer, The role of exergy in energy policy making, Energy Policy 30, 137 (2002)

[8] S. Dubey, S.C. Solanki, A. Tiwari, Energy and exergy analysis of PV/T air collectors connected in series , Energy and Building 41, 863 (2009)

[9] S. Nayak, A. Tiwari, Theoretical performance assessment of an integrated photovoltaic and earth air heat exchanger greenhouse using energy and exergy analysis methods, Energy and Building 40, 888 (2009) [10] B.J.Tsai, Y.L. Wang, A novel Swiss-Roll recuperator for the microturbine engine, Applied Thermal Engineering 29, 216 (2009)

[11] B.J. Tsai, K. Huang and C.H. Lee, Hybrid

Structural Systems of an active building envelope system (ABE), Advanced Materials Research, Vols.

168-170, 2359 (2011)

[12] B.J. Tsai, S.C. Lin and W.C. Yang, HVAC analysis of a building installed shape-stabilized phase change material plates coupling an active building envelope system. WSEAS Trans. On Heat and Mass Transfer, reviewing, (2011)

[13] W. Xiao, X. Wang and Y. Zhang, Analytical optimization of interior PCM for energy storage in a lightweight passive solar room. Applied energy, 86, 2013 (2009)

Figures

Fig. 1. Earth-air heat exchanger (EAHE)

Fig. 2. Self-sufficient building with integrated PV/T, SSPCM and EAHE as well as passive natural ventilation

Fig. 3. Model room (without roof) to be analyzed

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Fig. 4. Grid mesh of the model room and environments

(a) 1 min. (b) 10 min.

(c) 20 min. (d) 30 min.

Fig. 5. (a)-(d) Simulated indoor air temperature vs. time

(a) 1 min. (b) 10 min.

(c) 20 min. (d) 30 min.

Fig. 6 (a)-(d) Simulated indoor air temperature vs. time

Fig. 7 Twelve-hourly variation of indoor air temperature in HsinChu City

Fig. 8 Hourly variations of temperature of room air when operated with earth air heat exchanger (EAHE) for 24 h for a typical summer day.

Fig. 9 Hourly variations of temperature of room air when operated with earth air heat exchanger (EAHE) for 24 h for a typical winter day.

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Fig. 10 Variation of hourly useful energy (MJ) when operated with photovoltaic (PV/T) and earth air heat exchanger (EAHE) for 24 hr for a typical summer day.

Fig. 11 Variation of hourly useful energy (MJ) when operated with photovoltaic (PV/T) and earth air heat exchanger (EAHE) for 24 hr for a typical winter day.

Table 1：Properties of the building materials

Materials Ρ (kgm^-3)

Cp

(kJkg^-1℃^-1) K

(Wm^-1℃^-1) U (Wm^-2℃^-1)

SSPCM 850 1.0 0.2 -

Concrete 2500 0.92 1.75 -

Wood 500 2.5 0.14 0.875

Ground 2600 2.2 0.52 -

Table 2：Weather data of Hsin-Chu City

Season Temperature (℃)

Wind speed (ms^-1)

Pressure (Pa) Summer 29.6 6 (Southern wind) 1044.8

Winter 15.9 6.6 (Northern wind) 1017

Table 3： Convergence criteria

continuity x- velocity

y- velocity

z- velocity

energy 0.001 0.001 0.001 0.001 1e-06

Table 4: Average indoor air temperature vs. time for SSPCM+EAHE storage energy, absorption heat

Time

min concrete indoor- air

floor-

wood EAHE airout

1 302.99 302.75 302.98 302.74 302.74 5 302.95 300.42 302.92 302.74 300.53 10 302.91 299.38 302.84 302.74 299.38 20 302.83 299.56 302.68 302.74 299.68 30 302.76 300.52 302.53 302.74 300.63 60 302.55 300.87 302.14 302.74 300.97

Table 5: Average indoor air temperature vs. time for SSPCM+EAHE release energy, removal heat

Time

min concrete inside-a ir

floor-

wood EAHE airout 1 289.01 289.42 289.02 291.33 289.35 5 289.06 291.90 289.13 291.35 291.78 10 289.12 298.31 289.27 291.35 298.36 20 289.23 293.78 289.54 291.36 294.04 30 289.28 294.42 289.67 291.36 294.37 60 289.34 295.93 289.79 291.36 295.74

綠色建築三合一整合光伏電熱太陽能板(PV/T)空氣 收集器,地熱空氣交換器(EAHE)及鋪設穩態形狀相 變材料地板(SSPCM)的能量與最大可用能之分析研 究

蔡博章¹、張宇志²、賴世傑³

1中華大學機械工程研究所教授

2,3中華大學機械工程研究所研究生

國科會計畫編號. : NSC 99-2221-E-216-030 摘要

建築物越來越注重本身自己就是節能減碳有效率，因此自然通風、太陽能加溫與致冷、地溫空氣熱交換、

自然光線及避陽遮蔭…等自然被動式不需要消耗太多能量的設置，將是綠色建築的不二選擇，本研究三機一體將薄膜光伏電熱太陽能板空氣收集器(PV/T aircollector), 收集熱氣驅動氣流、搭配地溫空氣熱交換(EAHE)來的氣流與吸收透過窗戶或太陽能板光線的穩態形狀相變材料地板(SSPCM)之儲熱儲能，利用新設計分階相變活塞氣缸壓氣機作系統氣流、溫度的自然調配，整合出一棟完全被動式混成系統建築。考慮新材料與建築服務結合的綠色設計新觀念，再以一棟位於台灣新竹地區沒有空調的建物為探討對象，來數值分析仲夏夜晚通風情況下，氣、電及熱的需求與影響，分析時程含蓋日、月及年，先針對薄膜光伏電熱太陽能板與各次系統之物理數學模型(Model)驗證，再發展出被動式混成系統建築的完整物理數學模型，搭配MATHLAB、CFD 軟體協助而得到分析解及數值解。致於現在正在進行利用熵值公式(enthalpy formulation)及Voller 與Patankar 之控制容積數值技

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術求解二維暫態能量守恆搭配Stefan 移動邊界問題之福傳程式組Hybrid-HVAC，也將配合本棟被動式混成系統建築的個別次系統做程式修改為 Hybrid-HVACP，此程式可以幫忙材料作驗證，以及協助太陽能電池空氣收集器、地溫空氣熱交換及穩態形狀相變材料地板等系統作設計，為綠色建築-節能省能屋的最佳化設計與能量分析，提供有利的工具。

本研究將花費一年時間發展，以2010 年8 月1 日到 31日0am-24pm 及2011 年各個月新竹市的氣象資料當樣本，設定系統與次系統參數到本樣品屋，進行可行性評估、加溫與致冷能力分析、空調性能、次系統操作條件改變時如空氣流量改變，環境溫度與室內溫度的變化及隨氣候分級環境溫度變化時，本被動式混成系統建築的逐月逐年的能量分析…等，希望本研究成果能協助居民對各式各樣節能省能技術作選擇，並促成人們有健康、舒適地居住環境的美夢能成真。

關鍵字:光伏電熱太陽能板空氣收集器、地溫空氣熱交換、穩態形狀相變材料、空調系統、太陽能。

三、參考文獻

本研究所引用之文獻參考已載明於二、報告內容

之第七項文獻參考。另本研究成果及參與人員之衍生成果著作於文獻的有:

國際期刊論文有3篇: (Accepted)

1. Bor-Jang Tsai 、Koo-David Huang and Chien-Ho Lee , “Hybrid Structural Systems of An Active Building

Envelope System(ABE)”, Advanced material research, Vol. 168-170. pp. 2359-2370.

NSC-98-2221-E-216-047 ( EI: ISTP)

2. Bor-Jang Tsai ,Yu-Jhih Jhang and Teh-Chau Liau,

“Theoretical performance of integrated photovoltaic /thermal air collector, earth-air heat exchanger and greenhouse with a floor of shape-stabilized phase-change material: evaluation by energetic analyses”, Advanced Science Letters , in press. NSC-99-2212-E-216-030 (SCI: EI: IF:

1.35)

3. Bor-Jang Tsai, Sheam-Chyun Lin and Wei-Kuo Han,

“Thermal analysis of a high power LED multi-chip package module”, International Journal of Energy, Issue 4, Vol. 5, pp. 79-87, 2011

NSC-99-2212-E-216-030 (EI) 國際期刊論文有1篇: (Reviewing)

4. Bor-Jang Tsai、Sheam-Chyun Lin and Wei-Cheng Yang, “HVAC analysis of a building installed shape stabilized phase change material plates coupling an active building envelope system”, WSEAS

Transactions Journal, paper no. 53-895. (SCI: EI:

IF:0.9)

國外研討會論文有5篇:

1. Bor-Jang Tsai , Koo-David Huang and Chien-Ho Lee,” Hybrid Structural Systems of An

Active Building Envelope System(ABE)”, 2011 International Conference on Structures and Building Materials-Advanced Materials Research, 廣州, 中國, Jan. 2011.

2. Bor-Jang Tsai、Sheam-Chyun Lin and Wei-Cheng Yang, “Numerical HVAC Analysis of Shape-Stabilized Phase Change Material Plates Coupling an Active Building Envelope System in a Building”, WSEAS/NAUN International Conferences: 2nd International Conference on Fluid Mechanics and Heat and Mass Transfer 2011 (FLUIDSHEAT'11), Corfu Island, Greece., July 2011.

3. Bor-Jang Tsai, Sheam-Chyun Lin and Wei-Kuo Han,”

Thermal Analysis of a high power LED multi-chip Package Module for Electronic Appliances”, WSEAS/NAUN International Conferences: 2nd International Conference on Fluid Mechanics and Heat and Mass Transfer 2011 (FLUIDSHEAT'11), Corfu Island, Greece., July 2011.

4. Sheam-Chyun Lin, Bor-Jang Tsai and Cheng-Ju Chang, “Influence of Elevator Moving Pattern and Velocity on the Airflow Uniformity for an LCD Panel Delivery Facility”, WSEAS/NAUN International Conferences: 2nd International Conference on Fluid Mechanics and Heat and Mass Transfer 2011 (FLUIDSHEAT'11), Corfu Island, Greece., July 2011.

5. Bor-Jang Tsai ,Yu-Jhih Jhang, “Theoretical performance of integrated photovoltaic /thermal air collector, earth-air heat exchanger and greenhouse with a floor of shape-stabilized phase-change material:

evaluation by energetic analyses” ICETI 2011, 墾丁屏東台灣, Nov. 11-15, 2011

國內研討會有1篇、碩士論文有一:

1. 楊位盛-數值分析建築物整合鋪設穩態形狀相變材料板(SSPCM)及主動式外表帷幕系統(ABE)之空調效應,中華大學機械工程研究所碩士論文，臺灣新竹市 Jan. 2011.

1. Bor-Jang Tsai(蔡博章)，Pang-Wei Wu(張宇志),

“綠色建築三合一整合光伏電熱太陽能板(PV/T)空氣收集器,地熱空氣交換器(EAHE)及鋪設穩態形狀相變材料地板(SSPCM)的能量與最大可用能之分析研究

”，中國機械工程學會第二十八屆全國學術研討會論文集，中華民國一百年十二月十日、十一日，中興大學台中市。

四、計畫成果自評

本研究承蒙國科會經費贊助，非常感

謝，也在參與人員努力下，有不錯成果。

研究內容預期達成目標情況為:

預期完成工作項目

(1)Develop physical/ mathematic models for the passive hybrid system (OK)

(2)MATLAB 7.0 program develop to gain the analytical

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solutions of the passive hybrid system (OK) (3)Finite difference-Fortran program code Hybrid-HVACP programming (OK) (4)Energy & Exergy analysis methods (OK) (5)Heating/cooling,η,COP, ACH and HVAC performance of the hybrid system (OK)

本研究之主要成果: