DHL Group is the world's pioneer logistic company. The DHL Group connects people and markets and is an enabler of global trade. It aspires to be the first choice for customers, employees and investors worldwide. To this end, the Group focuses on growth in its profitable core logistics businesses and accelerating the digital transformation in all business divisions.

Founded in 1988 with offices in Kansas City, Austin and Denver, Dialectic is a non-traditional mechanical, electrical and plumbing engineering firm that brings buildings to life. With deep expertise in a range of verticals – including distribution, cannabis, multifamily, senior living and retail/restaurants – they know that true success comes with partnering as an extension of the team.

Digi-Key is one of the fastest-growing distributors of electronic components in the world. Digi-Key offers the world’s largest selection of electronic components in stock and available for immediate shipment. From prototype to production, they are here to fuel innovation all over the world.

Digital Twin Consortium is a global ecosystem of users ,who are driving best practices for digital twin usage and defining requirements for new digital twin standards. It coalesces industry, government and academia to drive consistency in vocabulary, architecture, security and interoperability of digital twin technology. It advances the use of digital twin technology from aerospace to natural resources.

Dimer LLC is the manufacturer of GermFalcon is a patented sanitizing device that instantly kills infectious germs on surfaces and in surrounding air. Using only ultraviolet-C (UVC) light, the kind used in hospitals, this highly-effective device is mobile and compact — no larger than a flight attendant’s food and beverage cart.

Dimplex offers a variety of both indoor and outdoor electric heating solutions that are attractive in design, as well as powerful in performance. The heaters range from fan-forced to infrared and are suited to different spaces requirements. Dimplex electric fireplaces lead the industry with flame effect technology and realistic media bed accessories.

Direct Expansion Solutions (DXS) specializes exclusively in variable refrigerant flow (VRF) air conditioning and heating systems. That means the entire team – from design engineers to technicians to trainers – are equipped to help one realize the benefits of installing a VRF system on their next project.

Distech Controls connects people with intelligent building solutions through their forward-thinking technologies and services. Their passion for innovation, quality and sustainability guides the business, which serves multiple market segments through worldwide business divisions, service offices and a superior network of Authorized System Integrators and Distributors.

DiversiTech Corporation is North America’s largest manufacturer of equipment pads and a renowned manufacturer and supplier of components and related products for multiple industries, including: HVACR, electrical, consumer hardware retail, electrical utility, automotive retail and pool and spa channel.

Since their company's beginning in 1946, they have been dedicated to providing exceptional service and superior heating, ventilation and air conditioning service and systems to East Texas residents at home and work. Customer satisfaction is their #1 priority.

dmg events is an international exhibition and publishing company with events across more than 25 countries in the Middle East, Europe, Africa, the Americas, and Asia. Headquartered in Dubai since 1989, it has expanded operations from this global hub city to Saudi Arabia, Singapore, Canada, South Africa, Egypt, and the UK, achieving impressive growth in emerging and mature markets.

DNV GL is a global quality assurance, software solutions and risk management company. They provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas, power and renewables industries. They also provide certification, supply chain and data management services to customers across a wide range of industries.

Dogu Air Conditioning (DOGU Iklimlendirme) started manufacturing ventilation and air conditioning equipment in Izmir, Turkey, back in 1999. It also manufactures Air Handling Units (AHUs), Rooftop Packaged Air Conditioning Units (Rooftop), Heat Recovery Devices, Air Distribution Equipment, and Kitchen Ventilation Devices according to European norms.

Donaldson Company helps solve some of the world's most complex filtration and contamination control challenges, and is one of the largest global providers of unique filtration technologies and high-quality filters and parts. Their filtration technologies and products are used every day, in a variety of industries and environments, including aerospace, agriculture, construction, manufacturing, mining, power generation, transportation, etc.

Done-Rite Plumbing & Rooter is the premier plumbing company in Orange, California, USA. They are a full-service plumbing contractor offering everything from water heater installation & repair, drain cleaning sewer line repair & installation, and general plumbing services. They service the entire Orange County area and can be out to any property in the area same-day for plumbing services.

Dongfang Electric Corporation (DEC) is a company based in Chengdu China, with businesses all over the world. With a long-term commitment to providing an integrated solution to global energy, transportation, environmental protection, and other infrastructure, they are determined to become top-notch energy and electromechanical equipment system integrator, service provider, engineering contractor, and overseas infrastructure investing.

Donovan & Sons, Inc. provides a full range of plumbing, heating, ventilation and cooling services for both residential and commercial customers. The company is made up of 5th generation plumbers and HVAC technicians dedicated to providing their customers with prompt, reliable, professional services.

Dornan Engineering Ltd. offers a full range of Mechanical, Electrical, Instrumentation, HVAC and Commissioning Services that will take any project from the construction drawings right through to final handover and commissioning.

Double Cool supplies and installs a range of refrigeration cabinet, acrylic door solutions throughout the UK. They work with supermarkets, chain and independent convenience stores, petrol stations, farm shops, garden centres and refrigeration engineers to provide a durable, cost saving, energy reducing solution for chiller cabinets.

Douglas Cooling & Heating is a full-service HVAC company that serves the higher Birmingham area. They strive hard to provide prompt and efficient solution.

Dowdle Heating and Air has been serving North MS since 1952. In 2012, Chris Powell merged with Dowdle to create Dowdle and Powell Heating and Air. They are an HVAC contractor. They offer service, sales, installation and fabrication of all HVAC equipment including air conditioners, thermostats, heat pumps, air filters, gas furnaces, programmable thermostats, humidifiers, ductless split systems.

Dowling Corporation is a pioneer HVAC/R mechanical services provider serving clients in New Hampshire, Southern Maine, and the North Shore of Massachusetts. Providing comfort and peace of mind since 1961.

Downriver Refrigeration Supply Co. is a renowned full line HVACR (Heating, Ventilation, Air Conditioning, and Refrigeration) distributor in the metropolitan Detroit area of the United States.

Dring Air Conditioning & Heating is a family-owned business which makes them a rare breed in this era of big box stores and Internet commerce. They first opened their doors in 1953, and as their core of loyal HVAC heating and cooling customers has grown, their area of service has expanded.

DT Air Conditioning & Heating is Texas' renowned expert heating and cooling company. They offer furnace and air conditioning services in and around Plano, Texas, USA.

DUCO Ventilation & Sun Control focuses on health in all its developments in the field of ventilation and sun protection systems, always with a nod to optimal occupant comfort and maximum energy efficiency.

Duct & Vent Cleaning of America, Inc. was founded in April of 1989 by Ron Eckman. As early as February of 1990, Duct & Vent Cleaning of America, Inc. joined NADCA, the HVAC Inspection, Maintenance and Restoration Association. In fact, they were the first company to be allowed membership that used portable hepa vacuums in the cleaning process.

Duct Care Inc. provide is providing Professional Duct Cleaning Service since 2008. They also provide Furnace Cleaning, AC Coils Cleaning, Dryer Vent Cleaning and Central Vacuum Cleaning services. Their Unique Duct Cleaning process allow them to meet or exceed NADCA Duct Cleaning Procedure guide lines. From using pressure guns to different snake agitating whips and tools, they aim to not only get the job done, but get the job done right.

For over 30 years, Duct Doctor USA has been providing quality air duct cleaning for both residential and commercial customers. Duct Doctor was founded by a board-certified allergist in 1985 with a mission to improve the air quality of homes and workplaces.

Ductcap Products Inc. are renowned manufacturers of temporary reusable duct end covers. These duct end covers help keep duct work clean during shipping, staging and during construction.