DigiCert is the only provider of enterprise-grade SSL, IoT and PKI solutions. The world’s top banks, e-commerce retailers, healthcare providers, manufacturers and technology companies rely on us to secure their digital properties and to protect the privacy and data integrity of their consumers. Computerworld named DigiCert one of the Top 100 Places to Work in IT.

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.

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.

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.

DM Select Services has proudly provided heating, cooling and plumbing services to clients all around the Northern Virginia (NOVA) area since 2009. We have physical offices located all over the NoVA area in Ashburn, Burke, Fairfax Station, Leesburg, and Winchester, so we can meet you wherever you are located. Our team brings a wealth of HVAC experience and is focused on delivering quick turnaround times on our installations at an affordable price.

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.

Donnelly is the most reliable mechanical contractor in New York City. Donnelly gives the clients peace of mind. Donnelly does this by providing the most innovative services and solutions through the experienced team. New York City’s premier provider of HVAC service, maintenance, and construction, as well as energy solutions.

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.

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.

Safe-T-Flush by Drain Shield is the new standard for condensate drain management, preventing leaks and clogs by ensuring a natural flow of condensation out of the drain line. The Safe-T-Flush system eliminates repetitive service calls, improve air quality with the unit, and prevent extensive and costly property damage.

Drake Refrigeration, Inc. is one of the best industrial chiller manufacturers. design custom industrial process chillers to meet a customer's particular .

Drews Marine GmbH supplies the maritime industry with highly individual or standardized solutions in the areas of refrigeration, air conditioning, ventilation, heating, pipeline construction and automation.

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.

Ducane is all about providing outstanding value in home heating and cooling. They provide residential heating and cooling products, packaged units, and split systems under 5-tons.

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.

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.

At Duct Hygiene they specialize in the servicing of commercial kitchen extraction systems, fresh air ventilation and Fire Damper Inspection & Testing. They provide maintenance services to both blue chip and private sector clients throughout the UK, performing over 7,500 service visits each year maintaining building safety and compliance.

Duke Energy is one of the largest energy holding companies in the United States. Its Electric Utilities and Infrastructure business unit serves approximately 7.5 million customers located in six states in the Southeast and Midwest.

DunAn Sensing offers high-performance OEM pressure sensors, transducers, and transmitters with MEMS packaging technology compatible with harsh media.

Dunphey-Smith takes pride in delivering not only quality service but also the best value and brand names in heating and cooling products.

Dunster Heat is based in the South West and is a nationwide biomass supplier and installer of vigas wood burning boilers and Akvaterm accumulators. Their biomass systems are combined to form an efficient biomass central heating system.