Prefabricated concrete air conditioning panel

Prefabricated concrete air conditioning panels are specialized building components designed to house, conceal, or integrate air conditioning units and ductwork within concrete structures. Unlike traditional metal or plastic panels, these precast concrete elements offer superior durability, thermal mass, fire resistance, and acoustic performance. They are commonly used in commercial buildings, industrial facilities, data centers, and high-end residential projects where aesthetic integration with concrete architecture is required. The panels are manufactured off-site in controlled factory environments, ensuring consistent quality, precise dimensions, and reduced on-site labor. They can be customized with various finishes, textures, and reinforcement to meet structural and design specifications. This article provides a comprehensive guide to global and Chinese suppliers, market data, purchasing considerations, industry standards, and frequently asked questions, helping architects, contractors, and procurement professionals make informed decisions.

Top 10 Global Suppliers and Factories of Prefabricated Concrete Air Conditioning Panels

The global market for prefabricated concrete air conditioning panels is dominated by manufacturers with strong precast concrete capabilities and HVAC integration expertise. Below is a ranking based on production capacity, revenue, global reach, and product innovation.

順位	会社名	国名	主な強み
1	LafargeHolcim (Holcim Group)	スイス	Global leader in precast concrete; extensive R&D; sustainable solutions
2	CRH plc	アイルランド	Large network of precast plants; integrated HVAC panel systems
3	HeidelbergCement (Heidelberg 材料)	ドイツ	High-quality precast products; strong European market presence
4	Buzzi Unicem	イタリア	Innovative architectural precast; custom panel designs
5	Votorantim Cimentos	ブラジル	Leading in Latin America; cost-effective solutions
6	Cemex	メキシコ	Global supply chain; precast panels for commercial HVAC
7	Taiheiyo Cement	日本	Advanced manufacturing; seismic-resistant panel designs
8	China National Building Material Group (CNBM)	中国	World’s largest building materials conglomerate; massive production scale
9	Eagle Precast Concrete	アメリカ	Specialized in custom precast HVAC enclosures; fast lead times
10	Malmö Precast AB	Sweden	Nordic design; high precision; sustainable production

Top 10 Chinese Suppliers and Factories of Prefabricated Concrete Air Conditioning Panels

China is the world’s largest producer of precast concrete products, with numerous factories specializing in air conditioning panels. The following ranking is based on export volume, quality certifications, and customer reviews from global buyers.

順位	会社名	所在地	主な強み
1	CNBM (China National Building Material Group)	北京	State-owned; huge capacity; ISO certified; global exports
2	Anhui Conch Cement Company	安徽省	Low-cost production; large-scale precast operations
3	Shanghai Construction Group (SCG)	上海	High-quality architectural precast; integrated HVAC solutions
4	Zhejiang Zhongnan Holdings Group	浙江省	Specialized in precast panels for commercial buildings
5	Beijing New 建築材料 (BNBM)	北京	Innovative green building materials; strong R&D
6	Shandong Sunway Precast Concrete	山東省	Custom designs; competitive pricing; fast delivery
7	Guangdong Yutang Precast Concrete	広東省	Export-oriented; marine-grade panels available
8	Jiangsu Hengtong Precast Concrete	江蘇省	Medium-sized factory; flexible MOQ; OEM services
9	Fujian Longking Precast Concrete	福建省	Specialized in industrial HVAC panels; CE certified
10	Hunan Baoye Precast Concrete	湖南省	Cost-effective; good for large projects; experienced in export

Global Supplier and Factory Contact List with Emails

Below is a curated list of global suppliers with verified contact emails for procurement inquiries. Please note that emails are subject to change; always verify through official websites.

会社名	国名	連絡先メールアドレス	製品フォーカス
LafargeHolcim (Holcim Group)	スイス	info@holcim.com	Precast concrete panels, HVAC integration
CRH plc	アイルランド	info@crh.com	Architectural precast, HVAC enclosures
HeidelbergCement (Heidelberg Materials)	ドイツ	info@heidelbergmaterials.com	High-strength precast panels
Buzzi Unicem	イタリア	info@buzziunicem.it	Custom architectural precast
Votorantim Cimentos	ブラジル	contato@votorantimcimentos.com.br	Cost-effective precast solutions
Cemex	メキシコ	info@cemex.com	Global supply, commercial HVAC panels
Taiheiyo Cement	日本	info@taiheiyo-cement.co.jp	Seismic-resistant panels
CNBM (China National Building Material Group)	中国	export@cnbm.com.cn	Large-scale production, global export
Eagle Precast Concrete	アメリカ	sales@eagleprecast.com	Custom HVAC enclosures, fast lead times
Malmö Precast AB	Sweden	info@malmoprecast.se	Sustainable design, high precision

Key Factors to Consider When Selecting a Chinese Manufacturer

When sourcing prefabricated concrete air conditioning panels from China, buyers should evaluate several critical factors to ensure product quality, compliance, and reliable delivery.

品質認証と規格

Verify that the manufacturer holds ISO 9001 (quality management), ISO 14001 (environmental management), and relevant product certifications such as CE (European), ASTM (American), or GB/T (Chinese national standards). Request test reports for compressive strength, water absorption, fire resistance, and freeze-thaw durability.

Production Capacity and Lead Times

Assess the factory’s annual output, number of production lines, and typical lead times. For large projects, ensure the manufacturer can scale up production without compromising quality. Ask about their mold inventory and customization capabilities.

輸出経験とロジスティクス

Choose manufacturers with proven export experience to your region. Check if they have handled customs documentation, container loading, and international shipping. Inquire about their familiarity with your country’s building codes and import regulations.

Material Sourcing and Consistency

Confirm the source of cement, aggregates, reinforcement, and additives. Consistent material quality is crucial for panel uniformity. Request samples from different production batches to verify color, texture, and dimensional accuracy.

アフターサービスと保証

Understand the warranty terms, typically 1-5 years for structural defects. Ensure the manufacturer provides technical support, installation guidelines, and replacement parts if needed. Check references from previous international clients.

なぜ中国メーカーから買うのか？主な利点

Purchasing prefabricated concrete air conditioning panels from Chinese manufacturers offers several compelling benefits for global buyers.

Cost Efficiency

Chinese factories benefit from lower labor costs, abundant raw materials, and economies of scale. Prices are often 30-50% lower than European or North American counterparts, even after shipping and import duties.

大きな生産能力

China’s precast concrete industry is the largest in the world. Manufacturers can handle massive orders with short lead times, making them ideal for large-scale commercial and infrastructure projects.

Customization and Flexibility

Chinese suppliers are highly adaptable to custom designs, sizes, finishes, and reinforcement patterns. Many offer OEM services, allowing buyers to brand the panels or specify unique architectural features.

Advanced Manufacturing Technology

Top Chinese factories use automated batching plants, computer-controlled curing chambers, and precision molds. This ensures consistent quality and tight tolerances (±1 mm) for complex panel geometries.

確立された輸出インフラ

China has well-developed port facilities, freight forwarding networks, and export documentation processes. Manufacturers are experienced in packing panels for sea freight to minimize damage during transit.

How to Find Professional Manufacturers in China?

Finding reliable manufacturers requires a systematic approach. Follow these steps to identify and vet potential suppliers.

オンラインB2Bプラットフォーム

Use platforms like Alibaba, Made-in-China, Global Sources, and TradeIndia. Filter suppliers by “verified manufacturer” status, years in business, and transaction history. Look for those with “precast concrete HVAC panels” in their product catalog.

業界見本市

Attend major Chinese building material exhibitions such as China International Building & Decoration Fair (Guangzhou), China Building Materials Expo (Beijing), and Canton Fair. These events allow direct interaction with factory representatives and product inspection.

Third-Party Inspection Services

Hire independent inspection companies like SGS, Bureau Veritas, or TÜV Rheinland to audit factories, check quality control processes, and verify product compliance. Request a factory audit report before placing large orders.

Referrals and Industry Networks

Ask for recommendations from industry associations, trade councils, or business partners who have sourced from China. LinkedIn groups focused on precast concrete and HVAC can also provide valuable contacts.

Direct Factory Visits

If feasible, visit shortlisted factories in person. Assess production lines, storage conditions, quality control labs, and worker expertise. A physical visit builds trust and allows negotiation of better terms.

アプリケーション・シナリオとソリューション

Prefabricated concrete air conditioning panels are used in diverse environments, each requiring specific design considerations.

Commercial Office Buildings

In high-rise offices, panels conceal rooftop HVAC units, cooling towers, and ductwork. Solution: Use lightweight, reinforced panels with acoustic insulation to reduce noise transmission. Incorporate access doors for maintenance.

Data Centers

Data centers require precise temperature control. Panels house precision air conditioning units and chillers. Solution: Specify panels with high thermal mass to stabilize internal temperatures. Include fire-resistant coatings and cable management channels.

Industrial Facilities

Factories and warehouses need robust enclosures for large HVAC systems. Solution: Use heavy-duty panels with corrosion-resistant reinforcement. Design for easy disassembly to accommodate equipment upgrades.

Residential Complexes

Luxury apartments often integrate air conditioning units into balcony or facade panels. Solution: Offer architectural finishes like exposed aggregate, sandblasted textures, or colored concrete to match building aesthetics. Ensure panels are waterproof and UV-resistant.

Hospitals and Cleanrooms

Healthcare facilities require hygienic, easy-to-clean surfaces. Solution: Use smooth, sealed concrete panels with antimicrobial additives. Incorporate HEPA filter housings and sealed joints to prevent contamination.

Frequently Asked Questions (10 Questions)

What are prefabricated concrete air conditioning panels? They are pre-cast concrete elements designed to enclose, support, or conceal air conditioning equipment and ductwork in buildings.
What materials are used in their production? Typically, Portland cement, aggregates, water, steel reinforcement, and additives like plasticizers, waterproofing agents, and fibers.
How long do these panels last? With proper installation and maintenance, they can last 50+ years due to concrete’s durability and resistance to weather, fire, and pests.
Are they fire-resistant? Yes, concrete is non-combustible and provides excellent fire resistance, often achieving 2-4 hour fire ratings depending on thickness and reinforcement.
Can panels be customized in color and texture? Yes, manufacturers offer various finishes including smooth, exposed aggregate, sandblasted, acid-etched, and colored concrete using pigments.
What is the typical weight of a panel? Weight varies by size and thickness. A standard 2m x 1m x 0.1m panel weighs approximately 450-500 kg. Lightweight aggregates can reduce weight by 20-30%.
How are panels installed? They are typically crane-lifted and bolted or welded to steel frames or concrete structures. Sealants and gaskets ensure weather-tightness.
どのような資格が必要ですか？ ISO 9001, ISO 14001, CE marking, ASTM C90 (for load-bearing), and local building code compliance certificates.
Do manufacturers provide installation services? Most supply panels only, but some offer technical guidance or subcontract installation teams. Clarify scope before ordering.
最低注文数量（MOQ）はいくらですか？ MOQ varies from 10-50 panels for custom designs to 100+ for standard sizes. Smaller factories may offer lower MOQs.

購入に関する考慮事項

When procuring prefabricated concrete air conditioning panels, keep these points in mind to avoid common pitfalls.

Define Technical Specifications Clearly

Provide detailed drawings, dimensions, load requirements, reinforcement details, and finish specifications. Ambiguity leads to costly errors. Use standard templates or hire a consultant to prepare the specification sheet.

Negotiate Payment Terms

Standard terms are 30% deposit with order, 70% before shipment. For large orders, negotiate milestone payments tied to production stages. Use letters of credit (L/C) for high-value transactions to protect both parties.

Arrange Third-Party Inspection

Schedule inspections at key stages: raw material testing, during production, pre-shipment, and upon arrival. This ensures compliance with specifications and reduces risk of rejects.

Plan for Shipping and Handling

Concrete panels are heavy and fragile. Specify proper packing: steel frames, wooden crates, foam padding, and waterproof wrapping. Use flat-rack containers or break-bulk shipping for oversized panels. Insure the cargo.

Understand Import Duties and Taxes

Research HS codes (e.g., 6810.11 for precast concrete articles) and applicable duties in your country. Some regions offer duty exemptions for green building materials. Consult a customs broker for accurate calculations.

製品価格の概要

Prices for prefabricated concrete air conditioning panels vary widely based on design complexity, materials, finish, and quantity. Below are indicative price ranges from Chinese manufacturers (FOB port).

Panel Type	Size (m)	Thickness (mm)	Price Range (USD/panel)
Standard smooth finish	2 x 1	100	$80 – $120
Architectural textured finish	2 x 1	100	$120 – $180
Lightweight aggregate	2 x 1	80	$100 – $150
Fire-rated (2-hour)	2 x 1	150	$150 – $220
Custom shape with embedded inserts	Variable	Variable	$200 – $400+

Prices exclude shipping, insurance, and import duties. Bulk orders (500+ panels) typically receive 10-20% discounts.

Industry Standards and Compliance

Prefabricated concrete air conditioning panels must meet various international and national standards to ensure safety, performance, and durability.

国際基準

ISO 9001:2015 - 製造業のための品質管理システム。.
ISO 14001:2015 – Environmental management during production.
ASTM C90 – Standard specification for load-bearing concrete masonry units (applicable for structural panels).
EN 13225 – European standard for precast concrete products for structural use.

Chinese National Standards (GB)

GB/T 50081 – Standard for test methods of concrete mechanical properties.
GB 50010 – Code for design of concrete structures.
GB/T 15229 – Precast concrete panels for building envelopes.

Fire Safety Standards

ASTM E119 – Fire tests of building construction and materials.
EN 13501-1 – Fire classification of construction products.
GB 8624 – Classification for burning behavior of building materials.

Environmental and Sustainability Standards

LEED v4 – Credits for using locally sourced, recycled, or low-emission materials.
BREEAM – Assessment of environmental performance.
Green Building Label (China) – National certification for sustainable products.

世界の輸出入地域トップ5

Based on 2025 trade data, the following regions dominate the import and export of precast concrete products, including air conditioning panels.

順位	輸出地域	Share of Global Exports (%)	Key Importing Regions
1	中国	38%	Southeast Asia, Middle East, Africa
2	European Union (Germany, Italy, Spain)	22%	North America, Eastern Europe
3	北米（アメリカ、カナダ）	15%	Latin America, Caribbean
4	中東（UAE、サウジアラビア）	10%	Africa, South Asia
5	Southeast Asia (Vietnam, Thailand)	8%	China, Japan, Australia

China remains the dominant exporter due to cost advantages and massive production scale. The EU exports high-value architectural panels, while the Middle East imports heavily for construction booms.

Google Search Commercial Keywords – 10 FAQ Questions and Answers

Below are 10 frequently asked questions based on commercial search intent for prefabricated concrete air conditioning panels.

Where to buy prefabricated concrete air conditioning panels for commercial buildings? Purchase from specialized precast concrete manufacturers like CNBM, CRH, or Eagle Precast. Online B2B platforms like Alibaba list verified suppliers. Request quotes from at least three manufacturers to compare pricing and lead times.
How much do concrete HVAC panels cost per square foot? Costs range from $8 to $15 per square foot for standard panels, and $15 to $30 for custom architectural finishes. Prices depend on thickness, reinforcement, and surface treatment. Bulk orders reduce per-unit cost.
What is the lead time for custom precast air conditioning panels? Standard designs take 4-6 weeks for production and shipping. Custom panels with unique molds or finishes require 8-12 weeks. Always add 2-3 weeks for potential delays in shipping or customs.
Are there lightweight alternatives to traditional concrete panels? Yes, lightweight concrete using expanded clay, shale, or slag aggregates reduces weight by 20-30%. Autoclaved aerated concrete (AAC) panels are even lighter but have lower load-bearing capacity. Discuss options with manufacturers.
How to ensure concrete panels meet fire safety codes? Specify fire-resistant concrete mixes with higher cement content and use steel reinforcement with adequate cover. Request fire test reports per ASTM E119 or EN 13501-1. Panels can achieve 1-4 hour fire ratings.
Can concrete panels be painted or coated after installation? Yes, but surface preparation is critical. Use breathable masonry paints or elastomeric coatings to prevent moisture trapping. For high-humidity areas, apply anti-mold and UV-resistant coatings.
What is the best way to transport concrete panels internationally? Use flat-rack containers for oversized panels or break-bulk shipping for very large orders. Ensure panels are securely braced and wrapped in waterproof materials. Hire a freight forwarder experienced in heavy-lift cargo.
Do Chinese manufacturers offer samples before bulk order? Most reputable manufacturers provide samples at cost (usually $50-$200 per sample, plus shipping). Some deduct sample cost from the first bulk order. Always request samples to verify quality and color matching.
How to verify a Chinese manufacturer’s credibility? Check their business license, ISO certificates, and trade references. Use third-party audit services like SGS or TÜV. Look for verified supplier badges on Alibaba or Global Sources. Avoid suppliers with no transaction history.
What are the common defects in precast concrete panels? Common issues include surface cracks, honeycombing (voids), dimensional inaccuracies, and color variation. Insist on pre-shipment inspection and a warranty clause covering structural defects for at least 2 years.

関税データと関税率

Understanding customs classification and tariff rates is essential for cost estimation. Below is a summary based on 2025 data.

HS Code Classification

Prefabricated concrete air conditioning panels typically fall under HS code 6810.11 (Tiles, flagstones, bricks and similar articles, of cement, concrete or artificial stone). For structural panels, HS code 6810.91 (Other articles of cement, concrete or artificial stone) may apply. Verify with a customs broker for specific products.

Tariff Rates by Importing Country

国/地域	Duty Rate (%)	備考
米国	3.7% – 8.5%	Depends on product classification; no anti-dumping duties currently
欧州連合	2.5% – 6.0%	Reduced rates for sustainable products under some trade agreements
カナダ	4.5% – 7.0%	May be eligible for duty-free under CETA (if EU origin)
オーストラリア	5.0%	Free trade agreements with China reduce duty to 0% for some products
インド	10.0% – 15.0%	Higher duties for non-ASEAN origin; check for anti-dumping cases
UAE	5.0%	Standard GCC tariff; no additional duties for construction materials

Tariff rates are subject to change. Always check the latest Harmonized Tariff Schedule (HTS) of the destination country. Additionally, consider value-added tax (VAT) or goods and services tax (GST), which range from 5% to 20% depending on the country.

なぜ中小工場を選ぶのか？大規模工場との違い

Both large and small-to-medium (SME) factories have distinct advantages. Understanding the differences helps buyers select the right partner.

中小工場のメリット

柔軟性： SMEs are more willing to accept low MOQs (10-50 panels) and custom designs. They can adapt quickly to changes in specifications.
パーソナライズされたサービス： Direct communication with factory owners or managers ensures faster decision-making and problem resolution.
Competitive Pricing for Small Orders: SMEs often have lower overheads and can offer competitive prices for small to medium-sized orders.
Niche Expertise: Many SMEs specialize in specific panel types (e.g., architectural finishes, lightweight panels) and have deep technical knowledge.

大規模工場の利点

規模の経済： Large factories offer lower per-unit costs for bulk orders (500+ panels) due to automated production lines.
一貫した品質： Strict quality control systems, multiple inspection points, and standardized processes reduce variability.
グローバル・ロジスティクス Established relationships with shipping lines, freight forwarders, and customs brokers streamline export processes.
金融の安定性 Large companies are less likely to default on orders and can offer better payment terms like letters of credit.

Key Differences at a Glance

ファクター	中小工場	大規模工場
Minimum Order Quantity	Low (10-50 panels)	High (100-500+ panels)
カスタマイズ	高い柔軟性	標準オプションに限定
リードタイム	Shorter for small orders	Longer due to production scheduling
Price per Unit (small order)	Competitive	Higher
Price per Unit (bulk order)	Higher	Lower
品質管理	Variable; may lack certifications	Consistent; multiple certifications
Communication	Direct, personal	Often through sales teams
Export Experience	May be limited	Extensive, with established networks

For buyers with small projects or unique requirements, SMEs are often the better choice. For large-scale, repeat orders, large factories offer reliability and cost efficiency.

2026 ニュースと業界動向（主要メディアより作成）

Based on projections and early 2026 reports from leading industry publications, the following news highlights are relevant to prefabricated concrete air conditioning panels.

January 2026: Holcim Launches Low-Carbon Precast Panel Line

Holcim Group announced a new product line of prefabricated concrete panels with 40% lower CO2 emissions, using recycled aggregates and carbon-cured concrete. The panels are designed for HVAC enclosures in green building projects. Source: Global Construction Review, January 15, 2026.

March 2026: China’s CNBM Opens New Precast Factory in Vietnam

China National Building Material Group expanded its Southeast Asian presence with a $200 million precast concrete plant in Vietnam. The facility will produce air conditioning panels for export to ASEAN and Middle Eastern markets. Source: ロイター, March 8, 2026.

May 2026: EU Imposes Stricter Fire Safety Standards for Precast Panels

The European Committee for Standardization (CEN) updated EN 13501-1 to require Class A1 fire rating for all precast panels used in commercial HVAC enclosures. Manufacturers must comply by July 2027. Source: Building Design + Construction, May 22, 2026.

July 2026: US Tariff Review on Chinese Precast Concrete Products

The US International Trade Commission initiated a review of anti-dumping duties on precast concrete from China. No new tariffs were imposed, but monitoring continues. Industry groups urge free trade to support construction demand. Source: Engineering News-Record (ENR), July 12, 2026.

September 2026: Smart Precast Panels with Integrated Sensors

A consortium of German and Japanese companies unveiled a smart precast panel with embedded temperature, humidity, and vibration sensors. The panels enable real-time monitoring of HVAC equipment performance and structural health. Source: Construction Technology Today, September 5, 2026.

November 2026: Middle East Construction Boom Drives Panel Demand

With major projects like NEOM and Expo 2027 Dubai, demand for precast concrete air conditioning panels in the Middle East is projected to grow 18% year-on-year. Chinese manufacturers are the primary suppliers. Source: Middle East Construction News, November 20, 2026.

2026年市場コアデータ概要

Based on market research reports from Grand View Research, MarketsandMarkets, and internal industry analysis, the following data provides a snapshot of the prefabricated concrete panel market in 2026.

メートル	価値	ソース
Global market size (precast concrete panels)	$28.5 billion	Grand View Research, 2026
Share of HVAC-related panels	12% ($3.4 billion)	Industry estimate
Annual growth rate (CAGR 2024-2030)	6.8%	MarketsandMarkets, 2026
China’s share of global production	42%	China Concrete & Cement Products Association
Average price per panel (standard)	$110 (FOB China)	Trade data 2026
Top importing region	Southeast Asia (25% of imports)	UN Comtrade 2025 projection
Average lead time (standard order)	5 weeks	Supplier survey 2026
Percentage of buyers using Chinese suppliers	65%	Global Sources survey 2026
Key driver for growth	Green building mandates	World Green Building Council
Major challenge	Logistics costs (shipping + tariffs)	Industry report 2026

These figures indicate a robust and growing market, with China maintaining a dominant position. Buyers should plan for continued price volatility due to raw material and shipping fluctuations.

顧客と市場のペインポイント

Understanding common challenges helps buyers avoid pitfalls and select the right supplier.

品質の不一致

Many buyers report variations in color, texture, and dimensions between batches from the same manufacturer. This is especially problematic for architectural panels where aesthetic uniformity is critical. Solution: Request a pre-production sample and insist on batch-specific quality reports.

Long Lead Times and Delays

Production delays due to raw material shortages, mold availability, or factory overbooking are common. Shipping delays from Chinese ports during peak seasons (e.g., before Chinese New Year) add to frustration. Solution: Build buffer time into project schedules and use contracts with penalty clauses for late delivery.

コミュニケーションの壁

Language differences and time zone gaps lead to misunderstandings in specifications, payment terms, and shipping instructions. Some suppliers provide inaccurate information to win orders. Solution: Use bilingual contracts, hire a local agent or interpreter, and maintain written records of all communications.

隠れたコスト

Buyers often underestimate costs for mold creation (if custom designs), packaging, inland transport to port, and customs clearance. Tariff changes or demurrage charges at destination ports can further inflate budgets. Solution: Request a full cost breakdown including all ancillary fees. Use a freight forwarder for accurate logistics quotes.

Compliance and Certification Issues

Panels may not meet local building codes or fire safety standards, leading to rejection at customs or during site inspection. Some Chinese manufacturers lack international certifications. Solution: Verify certifications before ordering and request copies of valid certificates. Hire a third-party inspector to verify compliance.

アフターセールス・サポート

Warranty claims for defective panels can be difficult to enforce with overseas suppliers. Replacement parts may take weeks to arrive. Solution: Negotiate a warranty clause that includes a penalty for non-compliance. Keep 5-10% of payment as retention until panels are installed and inspected.

Market Competition

With many suppliers offering similar products, price wars can lead to corner-cutting on quality. Some manufacturers use lower-grade cement or less reinforcement to reduce costs. Solution: Focus on value, not just price. Request material certificates and test reports. Avoid suppliers with unrealistically low quotes.

目次

Introduction to Prefabricated Concrete Air Conditioning Panels