Summary
The Delhi High Court reiterates the mandatory five-step test for inventive step, setting aside Energeo’s patent refusal for lack of proper reasoning.
In the case of Energeo Works India Private Limited v. Assistant Controller of Patents, the Delhi High Court set aside the refusal of a patent application for an air cooling system for pre-cooling ambient air. The Court held that the Controller wrongly limited the invention to a single feature and failed to apply the correct test for inventive step under Section 2(1)(ja) of the Patents Act. The Court also found that the refusal order lacked proper reasoning and did not follow the settled five-step test for obviousness. The matter was remanded for fresh consideration.
Background
Energeo Works India Private Limited (hereinafter “Energeo”) filed Indian Patent Application No. 202211052563 titled “Air Cooling System for Pre-Cooling Ambient Air.” The invention related to a system for pre-cooling ambient air received in an air-cooled chiller assembly in an HVAC system. The Controller refused the application under Section 15 of the Patents Act on the ground that claim 1 lacked inventive step under Section 2(1)(ja). The refusal was based on prior art documents D1 and D2 read with common general knowledge. The applicant appealed the refusal before the Delhi High Court under Section 117A of the Act.
Questions Before the Court
- Whether the Controller correctly identified and construed the claimed invention while assessing inventive step under Section 2(1)(ja)?
- Whether the Controller applied the correct legal test for determining obviousness, including the five-step test laid down in Hoffmann La Roche Ltd. v. Cipla Ltd.?
- Whether the refusal order was reasoned and compliant with principles of natural justice?
Arguments of the Appellant (Energeo Works India Private Limited)
Energeo submitted that the refusal order was unreasoned and arbitrary. Energeo argued that the Controller merely stated that the invention was obvious in view of D1 and D2 read with common general knowledge, without any claim-wise comparison or analysis. It contended that the Controller wrongly limited the invention to the feature of spraying mist of water to incoming air of the chiller. However, the claim 1 included several additional features such as a water recirculation system, air screen filter, drain pan, pumps and electronic controller, which were not disclosed in D1 or D2. It was further argued that the Controller failed to identify the inventive concept and did not apply the five-step test for determining obviousness as laid down in Hoffmann La Roche Ltd. v. Cipla Ltd. Energeo also argued that the Controller applied an incorrect “inspiration” test instead of the statutory obviousness test and relied on titles of prior art documents rather than their actual teachings.
Arguments of the Respondent (Assistant Controller of Patents)
The Controller defended the refusal order as reasoned and in accordance with the Patents Act. It submitted that the main feature of spraying mist of water onto the air-cooled chiller assembly was explicitly disclosed in both D1 and D2. The additional features such as water recirculation system, air filters, drain pans, pumps and electronic controller were common general knowledge in the field of air conditioning and refrigeration. The Controller maintained that these features could also be inspired from ordinary air coolers available in the market and that combining D1/D2 teachings with such common general knowledge rendered claim 1 and the dependent claims obvious. The Controller asserted that the invention did not demonstrate technical advancement or economic significance so as to satisfy Section 2(1)(ja).
Court’s observations and Analysis
The Court carefully examined the impugned refusal order and observed that the Controller wrongly limited the invention to the feature of spraying mist of water to incoming air of the chiller by selectively referring to parts of the specification. According to the Court, the claims had to be read as a whole and in light of the complete specification. The Court observed that claim 1 included several structural and functional features such as a water recirculation system with an air screen filter and drain pan, pumps supplying pressurized water, and an electronic controller.
The Court further observed that the Controller failed to adopt the five step test for determining obviousness as elucidated in Hoffmann La Roche Ltd. v. Cipla Ltd., 2015 SCC OnLine Del 13619. According to the Court, the five steps require identification of the person skilled in the art, identification of the inventive concept, determination of common general knowledge at the priority date, identification of differences between prior art and the claimed invention, and determination of whether those differences would have been obvious without hindsight.
The Court stated that this sequential analysis was not undertaken in the refusal order. The Court also noted that although the Controller acknowledged that D1 and D2 did not explicitly disclose the water recirculation system, air filter, drain pan and electronic controller, the Controller concluded without reasoning that these were common features that could be used without mechanical ingenuity. According to the Court, there was no basis or material cited to support the finding that these features formed part of common general knowledge. The Court also observed that the statement that extra features may have been inspired from air coolers in the market reflected a hindsight approach, which is impermissible in assessing inventive step under Section 2(1)(ja).
The Court held that the refusal order did not contain a proper analysis of prior art documents D1 and D2, nor did it explain how a person skilled in the art would combine them to arrive at the claimed invention. The Court found that the reasoning was inadequate and legally unsustainable.
Conclusion
The Court set aside the impugned order refusing the patent application. The Court remanded the matter to the Patent Office for fresh consideration in accordance with law. The Controller has been directed to decide the matter within four months from the date of receipt of the order after granting Energeo an opportunity of hearing.
Case Citation: Energeo Works India Private Limited v. Assistant Controller of Patents, C.A.(COMM.IPD-PAT) 21/2025 (Del. H.C. Jan. 30, 2026).
Article review and accessibility review: Gaurav Mishra